Why do I feel like a waste of oxygen?

I was drunk, stoned, or overmedicated for many years, largely in an attempt to escape the terror of mental illness which, by the way, doesn't work. None of my four children enjoyed the stability and comfort that I had in childhood. For reasons of selfishness and greed, I have done a lot of wrong and now I am fortunate to be able to help others struggling with major challenges for love and for free. But it isn't enough. Even major breakthroughs only help me feel clean for a little while. I have been helped so much by others that I feel as if I have escaped from hell, but what can I ever hope to do to be worthy of that? I bubble over with gratitude but I don't like the man in the mirror.