Imam Ali P.B.U.H. says "Doubt extinguishes the light of heart". I think that Shaytaan’s most powerful weapon for a believer is doubt. And needless to say I am entangled in it. I need someone’s help. I would really appreciate it if you could help me. The topic of doubts is purity. In Quran Allah says "We do not burden a soul more than it can bear" but at this point I am feeling I can’t bear it any longer.

Having too much doubts should be ignored. Allah doesn’t not want to burden you. In Tahara (purity) don’t listen to whispering of Satan and ignore the doubt

You may also benefit from therapy related to OCD or get CBT therapy