I am so sorry if I say anything bad here and I am so sorry for the long post, as well.
I am 15 years old but I have this problem with kufr. A while ago, I would say things like mistakes or silly things but I learned if it’s a mistake or forgetfulness then it doesn’t count. But I didn’t know at the time. Gradually, it started to get worse where I had to recite the declaration of faith every day after I had thoughts or feelings or said something. Also, I have problems in prayer and purity. Before I pray, I have to recite it because I tend to get upset because of the hardship in prayer, purity, and me doubting I am a Muslim. I would try to make ablution for prayer but I would have to redo it again because I keep making mistakes or I fear that I may have invalidated it in a way. This frustrated me so when I go to pray, I feel upset. When I try to pray, I have trouble with reciting the words or I make mistakes and it takes me like 15 minutes pray. I am mostly focused on whether I am saying something right rather than what it means. So, when the prayer is over, I don’t feel that calm sometimes, I just feel upset. Nowadays, things have gotten a bit rough. I always get these bad thoughts and feelings about Allah out of sadness. But I feel so sad when I have to recite the declaration of faith because of that. I don’t want to apostatize, I hate it. I want to be a Muslim and pray, read Quran and be happy! But it’s kind of hard being positive because the shaytaan, I am pretty sure, is continuously telling me I am going to go to hellfire for my sins in the past, as well Me, as a weak person, just agrees with it and cries. Even though I repented from them.
But I am so scared. Because of the hardship in prayer, purity, and doubting I am a Muslim, I think I get scared to read fatwas out of fear that things may become harder which is not good Astagfirullah. For example, once when someone, may Allah give them many blessings, said we were going to be held accountable if we agreed with something of kufr (I am sorry, I am not so sure) then I just burst into tears because I got so scared and I thought things were gonna get so hard even more. I know I keep doing things wrong with thinking badly of Allah Astagfirullah. I have trouble completing my school work at times because of these issues about prayer and purity and kufr so I feel stressed which is a factor in me potentially committing kufr but I feel like giving up so I am afraid. But please, is there any ruling I can follow that could potentially be easy for me, because I feel so scared I am going to give up everything. JazakAllahu Khairun.