I'd appreciate some advice...?

I'm a sensitive person and really easily feel awkward and left out in social situations. I will contribute to a conversation and end up saying something I won't realize is "stupid" until a parent or friend will point out my error. I already know that I rarely know what to say, and therefore, I feel like absolute ****. I get defensive and take so much out on my self. Honestly, I can remember every mistake I've ever made and I feel that same shi**y feeling that I felt when it happened, now. I do see a therapist who is a wonderful individual, and I am taking an anti-depressant which works to help with the "sadness" but I'd really like someone to tell me there's a way to not bug out about my mistakes, and not necessarily forget them, but not be so affected by stuff that happened in the third grade instead of prescribing another pill. Advice on how to build a filter regarding what I say or do would be nice too... Thanks so much to all of you that reply :)