I forgive myself by accepting it's in my past. I am an addict and addicts do things when they are in the throes of addiction that non-addicts simply don't do. It's just that simple.
Being around people from my past is another matter entirely
I haven't quite gotten to the point where I'm comfortable being around past acquaintances and old friends or family members yet. But I do come from a very dysfunctional family background, and I'm about 90% certain that remaining distant from my family supports my sobriety at this point. Friends do get tired of the addict behavior. And they do lose patience and trust. I guess I'm just not interested in being around many people from my past, as I had moved away from home long ago, and lost touch with all of them anyway. It just happened with school, job moves, etc. And I have never been one to make lots of friends easily, so most of my other "friends" in recent years were just acquaintances anyway.
I guess it'd be hard had I lived in the same town throughout my drinking career. I honestly don't know how I'd handle reconnecting in that situation.
Forgiving yourself will come in time. It helps for me to understand how addiction works in the brain, and it helps for me to do things that increase my self-esteem on a daily basis. I think with time, and by doing good things to bolster yourself regularly you'll see that the shame and guilt do lessen.