I lost the 20 year old me! How do I find him?

I was a really popular, happy-go-lucky guy from 17-21. I drank heavily, did lots of drugs and had a beautiful girlfriend. I split up with the girl, (she was the love of my life but I wasn't thinking straight) became depressed, gave up the gear and the booze, started working out, rediscovered catholicism (but not in a ott jesus freak way) and smartened up at work. This took about 3 years and I'm now 25. I'm no longer depressed but I'm this completely different guy. I'm shy around women and I avoid social situations, especially those involving old acquaintances. Anybody in the same boat? Any advice would be greatly appreciated.