I've done that too, pegasus. I call it the "what ifs."
But you need to look at what you HAVE done considering your past. If you start there and realize, hey, I didn't do so bad after all, it might help you.
It took me a long time to "get" that, but after T pounding it into my head, and me finally cutting myself some slack, I know she's right. I've done pretty good, all things considered.
So have you.