Voices,
I've done the despair and depression thing, several times. and a main reason was that my parents constantly compared us as kids and judged (you'll never be as good at this as x).
Therapy is hard. It's difficult to face the truth about ourselves, and change is probably hardest of all. But these things are real, and lead to a real, better life.
You are no more a sinner than anyone else. If you are still religious, you know that the Bible teaches this too; if not, sin is a useless concept anyway!
You are a person whom life has given the insight and motivation to pursue a hard path that will lead to better things. Use it, work through it and I wish you all happiness.
Retro