You sound like I did years ago. I gave it up when I realized: my kids have a wonderful father (we have been married 28 years), other kids deal with all sorts of problems in their childhood, my bipolar is NOT my fault, my kids are happy.
During my "normal" times, I worked my butt off for my kids. During the down times, I did my best.
One of my kids has her masters. The other two are successfully in college. I have a close relationship with all of them. Things aren't perfect but they are what they are.

One thing I will say: I have stopped lying to everyone. If I can't attend something I will say "I am not feeling well, I'd love to come but I suffer from depression and it is hard to get out right now." My close friends all know about my bipolar. I am happier than I have ever been not to have to lie and feel shame.