Well, I know my answer isn't for everyone, but I forgave myself through Jesus Christ. I'm also a member of AA but I tend to see the AA program as a form of christianity, to me it has the same message that JC gave us. One of the messages given by christianity is that he died so that we could live and be forgiven. Of course alot of people who are much more learned than me might argue that he didn't die on the cross and so on but I've decided that for me that doesn't matter. Its the spirit of christ developed over the years by human beings who have also been in touch with a higher power. Christianity gives a solution for human guilt (which as Captainzing points out, isn't exclusive to alkies). Guilt has been around for a long time - you are not alone.
Christianity and the AA way of living is logical too really. It teaches us how to get on with people so we can all have a better life and it gives us a way of getting rid of guilt (may have to work on this - doesn't always happen over night). If we don't get rid of it we can't live properly and that spirit of life wants us to live and embrace life!
I find it helpful to know that I am not alone, people have been feeling like this for thousands of years and a solution has been found because people have spent so much to find it.