What should I do about the recurring thought of interrupting prayer while performing it, and am I obligated to repeat it for the third time, knowing that I am someone who is often afflicted with doubt concerning purity, Al-Fatihah, prostrations, and rak'ahs?

We advise the questioner to continue her prayer and ignore thoughts and whispers, and not to repeat the prayer no matter how much she doubts its validity. Even if hesitation occurs regarding interrupting the prayer, some scholars hold that it does not invalidate it, and this is the most correct opinion, because the original state is the continuation of the intention. Therefore, her prayer is valid, and her hesitation has no effect.