What was I thinking?

Question for the group: How do you deal with post-therapy or post-medication regret?

Background: 52 year old male, living in San Diego. Was in therapy for several months (need to find a new therapist due to schedule change) and have been on Wellbutrin for several months. During that time, it's like my eyes have been opened. I realize now how bad things were, how many mistakes I made, the harm I caused. The regret I feel for my choices is almost too much. I finally see how so many mistakes were just to distract myself from how empty and depressed I was, but I can't change my past and I barely know how to fix my future.

Anyone else dealing with the same thing? Any suggestions would be appreciated.