So i was praying and than i realized something was wrong when i was reciting surah al-fatiha and i felt like i was making mistakes and than i was really confused than i searched surah al-fatiha i saw 2 lines were different than what i was reciting all these days and i am still not sure if it happend only that time or i was doing this all along after this i was really dissapointed how all my Namaz went to waste and was depressed and i still can't get if i was really doing it wrong all this time or if it was just this time please help and tell me what should i do
In brief, the ruling on the person who makes mistakes that alter the meaning is one of the following. Your case is point #3:
If he made the mistake intentionally, his prayer along with the prayer of the people he is leading in prayer are invalid according to the agreement of scholars.
If he made the mistake out of forgetfulness, his prayer is valid according to the agreement of the scholars.
If he is unable by nature to pronounce it properly and he is unable to learn, then the ruling is the same (i.e. the prayer is valid) because he cannot pronounce it properly.
If he is ignorant and he is eligible to learn, then there is a difference of opinion regarding the ruling in this regard, regardless of whether he is able to learn or not, and whether he can be led in prayer by someone who does not make mistakes or not. The most valid opinion about him is that the prayer of the people led by him is valid, and so is his prayer with greater reason." [Haashiyat Ad-Dusooqi]
If these doubts about recitation are mere Waswaasah (obsessive whispers), then the questioner should disregard them in the future and seek refuge with Allah from the accursed satan; and her prayer is valid.
Source here in English: https://www.islamweb.net/en/fatwa/366616/mistake-in-al-faatihah-in-prayer