I hate to say the obvious, but it kind of sounds like you should be talking to a therapist about this. It sounds absolutely horrible to carry around all that guilt, guilt that seems pretty baseless.

Bar getting professional help, perhaps it would help to kind of copy AA and seek forgiveness for whatever transgressions (real or imaginary) you feel you need forgiveness for. I would write out a list of everything you feel guilty for and try to figure out who you have possibly hurt in that process. If you are a church going person, perhaps talking to someone in your church (priest, minister, rabbi, etc.) might help.

Best of luck to you.