Are my previous prayers, before my illness, considered valid, or must I make them up, knowing that I do not know if what comes out of me comes out before or after ablution, and am I sinful for delaying asking this question?

Your previous prayers before your illness are valid, even if you found out about the presence of impurity after the prayer, as long as you were unaware of it at the time of the prayer. Therefore, you are not obligated to repeat them, according to the correct opinion. This question is often a continuation of the obsessive-compulsive disorder you are suffering from. There is no sin in your delay in asking this question; it is merely a whisper (waswasah), and if you stop indulging in these whispers, it would be better for you.