Ever since I asked Allah to forgive all of my past, present, and future sins, I'm enduring more hardship and feeling more unhappy. I read that God would test us in compensation for our sins. If that's what's happening to me, then I can't really take it and I'll tell him to forget it.
I would not say that but Yes, Allah test his people and will reward them in heaven. but you said "hardship and unhappy" Allah don't gave a person what he can't bare and Allah don't make his people unhappy.
Here is Ayat:
Allah does not impose on any self any more than it can stand. For it is what it has earned; against it, what it has merited. Our Lord, do not take us to task if we forget or make a mistake! Our Lord, do not place on us a load like the one You placed on those before us! Our Lord, do not place on us a load we have not the strength to bear! And pardon us; and forgive us; and have mercy on us. You are our Master , so help us against the people of unbelievers.
(Surat al-Baqara, 286)
When you move toward Allah, He will run toward you and you will have peace.
What I think you are feeling is your resistance from Devil. Remember Devil is not our friend when he sees anyone going toward Allah he will do what every he can do to stop you. So don't stop until Allah take you in his hand.
For truly with hardship comes ease; truly with hardship comes ease. So when you have finished, work on, and make your Lord your goal!
(Surat al-Inshirah, 5-8)
We will ease you to the Easy Way.
(Surat Al-A‘la, 8)
Given the hardships are not a consequence of your own unwise decisions (so that could be fixed by working out a wise solution), then there's no better way of tackling it than viewing your suffering as a trial imposed by Allah.
You will come out with heightened fortitude and empowered soul, if you seek strength and solace in Him as your struggle; and it will leave you desperate and impoverished, if you only keep grumbling and cursing it in desperation. So try to master the art of turning your hardships into heroic accomplishments by relying on Him, may you realize the truth in this Quranic wisdom that:
Have We not expanded your chest for you, (oh, Prophet!) (1) and relieved you of your burden (2) that weighed down your back? (3) Have We not raised your fame? (4) Indeed, hardship is followed by ease, (5) indeed, hardship is followed by ease! (6) So, when you have finished (your prayer), labor (in supplication), (7) and let your longing be for your Lord (in humility). (8) Surah as-Sharh, 94