Marriage is Sunnah, if you turn away from it (deny its advantages, not having interest in marriage, and etc.) it will be forbidden , but if you simply postpone it to a better situation it will be ok, you may need to prepare for it or else find a better woman. However, there is a simple rule in Islam an example of which being stated in [17:29] about spending in charity:
Make not thy hand tied (like a niggard's) to thy neck, nor stretch it
forth to its utmost reach, so that thou become blameworthy and
destitute.
the rule states that commit the encouraged deeds to the extent that you will not then get blameworthy and destitute. According to this simple rule many scholars encourage people to marry only if they have been prepared for it, otherwise know it as discouraged unless it has become obligatory (for example if the person is going to commit a sin). However, this rule never determines a specific threshold for all the Muslims, as not all the Muslims are the same in the sense of faith and trusting in Allah. So that you should decide about your marriage by yourself, but if the question is a general question then we can speak in a way that may be of practical value for some and only of theoretical value to others (no Muslim would ever deny its value anyway, as it would be equal to denying Quran or turning away the holy prophet's tradition). This speaking starts from the following verses in Quran:
وَمَا مِن دَابَّةٍ فِي الْأَرْضِ إِلَّا عَلَى اللَّهِ رِزْقُهَا
وَيَعْلَمُ مُسْتَقَرَّهَا وَمُسْتَوْدَعَهَا كُلٌّ فِي كِتَابٍ مُّبِينٍ
There is no moving creature on earth but its sustenance dependeth on
Allah: He knoweth the time and place of its definite abode and its
temporary deposit: All is in a clear Record. [11:6]
or
وَكَأَيِّن مِّن دَابَّةٍ لَّا تَحْمِلُ رِزْقَهَا، اللَّهُ يَرْزُقُهَا
وَإِيَّاكُمْ وَهُوَ السَّمِيعُ الْعَلِيمُ
How many are the creatures that carry not their own sustenance? It is
Allah who feeds (both) them and you: for He hears and knows (all
things). [29:60]
which clearly state that sustenance for any moving creature is provided by Allah, that is, any moving creature (say, alive creature in the sense we usually define an alive species) is given its own proportion of sustenance, such that no creature can eat the sustenance put aside for another creature, whatever that you see someone is eating is certainly his own sustenance, we can only make our sustenance licit or ill-gotten. This is very critical to note no one dies before his sustenance (food to eat, air to breath, and etc.) is finished, so that the holy prophet's Hadith stating that eating less would always elongate the life! However, this needs a short comment to be added at this point: according to Ahlul-Beyt --peace be upon them-- sustenance is provided for the aspirant of sustenance, that is, this guarantee is never an encouragement for laziness, Allah doesn't always send the creature its part but usually hides its part in a process for the creature to go for it and reach it where and when it was planned. That providing sustenance to all the moving creatures in general and to humans in particular is guaranteed by Allah is as much important that Allah even use it as a witness that no other god exists aside him:
أَمَّن يَبْدَأُ الْخَلْقَ ثُمَّ يُعِيدُهُ وَمَن يَرْزُقُكُم مِّنَ
السَّمَاءِ وَالْأَرْضِ أَإِلَٰهٌ مَّعَ اللَّهِ قُلْ هَاتُوا
بُرْهَانَكُمْ إِن كُنتُمْ صَادِقِينَ
Or, Who originates creation, then repeats it, and who gives you
sustenance from heaven and earth? (Can there be another) god besides
Allah? Say, "Bring forth your argument, if ye are telling the truth!"
[27:64]
and
أَمَّنْ هَٰذَا الَّذِي يَرْزُقُكُمْ إِنْ أَمْسَكَ رِزْقَهُ بَل
لَّجُّوا فِي عُتُوٍّ وَنُفُورٍ
Or who is there that can provide you with Sustenance if He were to
withhold His provision? Nay, they obstinately persist in insolent
impiety and flight (from the Truth). [67:21]
You may then ask why some are given more and some are given less? This is what Allah has addressed as follows:
اللَّهُ يَبْسُطُ الرِّزْقَ لِمَن يَشَاءُ مِنْ عِبَادِهِ وَيَقْدِرُ
لَهُ إِنَّ اللَّهَ بِكُلِّ شَيْءٍ عَلِيمٌ
Allah enlarges the sustenance (which He gives) to whichever of His
servants He pleases; and He (similarly) grants by (strict) measure,
(as He pleases): for Allah has full knowledge of all things. [29:62]
and there is a wisdom behind that which is off-topic to this question. According to a Hadith from Imam Ali --peace be upon him-- "اَلدَّهرُ يَومانِ : يَومٌ لَكَ وَ يَومٌ عَلَيكَ فَإذا كانَ لَكَ فَلا تَبطَر وَ إذا كانَ عَلَيكَ فَاصطَبِر" (meaning: time consists of two days, one day for you and one day against you, when it is for you then don't get willful and slaphappy and when it is against you be patient), and this Hadith can well be valid also about the economical issues, that is, the sustenance issue, that is, anyone may experience both a state of being wealthy and indigence, during his/her life, to some extent. Anyway, based on these concept in Islam, when you say "barely have enough energy to pray 5 times a day" it is completely considered as wrong, as Quran says:
وَأْمُرْ أَهْلَكَ بِالصَّلَاةِ وَاصْطَبِرْ عَلَيْهَا لَا نَسْأَلُكَ
رِزْقًا نَّحْنُ نَرْزُقُكَ وَالْعَاقِبَةُ لِلتَّقْوَىٰ
Enjoin prayer on thy people, and be constant therein. We ask thee not
to provide sustenance: We provide it for thee. But the (fruit of) the
Hereafter is for righteousness. [20:132]
that is, we are guaranteed to earn what is our part if we simply work, the part may be small or large but this is our part, we will not ever earn more than we are hidenly given sustenance by Allah, so it would be better for us to concentrate on the reason we are here in this world, not mainly focusing on how to survive and remain alive in this world, we are here to improve in humanity and get closer to Allah. If someone tries to please Allah by undergoing his rules, then Allah gives him his sustenance from a source he could never have imagined:
وَيَرْزُقْهُ مِنْ حَيْثُ لَا يَحْتَسِبُ وَمَن يَتَوَكَّلْ عَلَى
اللَّهِ فَهُوَ حَسْبُهُ إِنَّ اللَّهَ بَالِغُ أَمْرِهِ قَدْ جَعَلَ
اللَّهُ لِكُلِّ شَيْءٍ قَدْرًا
And He provides for him from (sources) he never could imagine. And if
any one puts his trust in Allah, sufficient is (Allah) for him. For
Allah will surely accomplish his purpose: verily, for all things has
Allah appointed a due proportion. [65:3]
This needs a Muslim to trust in Allah, this needs more that being a Muslim merely while speaking, but a believer with a true faith in hearth. Then Allah states that:
قُلْ تَعَالَوْا أَتْلُ مَا حَرَّمَ رَبُّكُمْ عَلَيْكُمْ أَلَّا
تُشْرِكُوا بِهِ شَيْئًا وَبِالْوَالِدَيْنِ إِحْسَانًا وَلَا
تَقْتُلُوا أَوْلَادَكُم مِّنْ إِمْلَاقٍ نَّحْنُ نَرْزُقُكُمْ
وَإِيَّاهُمْ وَلَا تَقْرَبُوا الْفَوَاحِشَ مَا ظَهَرَ مِنْهَا وَمَا
بَطَنَ وَلَا تَقْتُلُوا النَّفْسَ الَّتِي حَرَّمَ اللَّهُ إِلَّا
بِالْحَقِّ ذَٰلِكُمْ وَصَّاكُم بِهِ لَعَلَّكُمْ تَعْقِلُونَ
Say: "Come, I will rehearse what Allah hath (really) prohibited you
from": Join not anything as equal with Him; be good to your parents;
kill not your children on a plea of want;- We provide sustenance for
you and for them;- come not nigh to shameful deeds. Whether open or
secret; take not life, which Allah hath made sacred, except by way of
justice and law: thus doth He command you, that ye may learn wisdom.
[6:151]
That is to say, to any child Allah specifies a sustenance, so that no matter how many child a person would have Allah would provide the family with enough sustenance (enough in the view of Allah is not always as expected by people!). Even if people want Barakat in their money they may try to make more and more children, because Allah will put their sustenance in the family's basket! (Note that guests eat in the host's house, consuming their foods and maybe even some other goods, but they are also introduced as sources of barakat) Also mention the following verse:
قَدْ خَسِرَ الَّذِينَ قَتَلُوا أَوْلَادَهُمْ سَفَهًا بِغَيْرِ عِلْمٍ
وَ*حَرَّمُوا مَا رَزَقَهُمُ اللَّهُ* افْتِرَاءً عَلَى اللَّهِ قَدْ
ضَلُّوا وَمَا كَانُوا مُهْتَدِينَ
Lost are those who slay their children, from folly, without knowledge,
and forbid food which Allah hath provided for them, inventing (lies)
against Allah. They have indeed gone astray and heeded no guidance.
[6:140] {I doubt if this verse is usually translated and even interpreted in a precise manner! Allah has put a sustenance for the family and they are destructing this opportunity with their own hands}
Keeping in mind all the above witnesses and reasonings, now I grab your mention to the following verse:
وَلْيَسْتَعْفِفِ الَّذِينَ لَا يَجِدُونَ نِكَاحًا حَتَّىٰ يُغْنِيَهُمُ
اللَّهُ مِن فَضْلِهِ وَالَّذِينَ يَبْتَغُونَ الْكِتَابَ مِمَّا
مَلَكَتْ أَيْمَانُكُمْ فَكَاتِبُوهُمْ إِنْ عَلِمْتُمْ فِيهِمْ خَيْرًا
وَآتُوهُم مِّن مَّالِ اللَّهِ الَّذِي آتَاكُمْ وَلَا تُكْرِهُوا
فَتَيَاتِكُمْ عَلَى الْبِغَاءِ إِنْ أَرَدْنَ تَحَصُّنًا لِّتَبْتَغُوا
عَرَضَ الْحَيَاةِ الدُّنْيَا وَمَن يُكْرِههُّنَّ فَإِنَّ اللَّهَ مِن
بَعْدِ إِكْرَاهِهِنَّ غَفُورٌ رَّحِيمٌ
Let those who find not the wherewithal for marriage keep themselves
chaste, until Allah gives them means out of His grace. And if any of
your slaves ask for a deed in writing (to enable them to earn their
freedom for a certain sum), give them such a deed if ye know any good
in them: yea, give them something yourselves out of the means which
Allah has given to you. But force not your maids to prostitution when
they desire chastity, in order that ye may make a gain in the goods of
this life. But if anyone compels them, yet, after such compulsion, is
Allah, Oft-Forgiving, Most Merciful (to them) [24:33]
So that anyone who is afraid of getting married like when feels not to be yet ready for that may instead try to keep himself chaste, and of course if someone is afraid of committing a sin (not able to keep himself chaste) this verse is not for him!
Godspeed.
