Forgiveness of Sins

Every time I pray the creed I say that I believe in the forgiveness of sins, but somehow this hasn't truly sunk into me. It's one in a series of phrases I recite; kind of a mindless checklist. This is truly a rather disturbing little epiphany for me; there it is, in the familiar creed I've said since I was a child, yet I have trouble believing that God can forgive me for leaving the church and my faith for about ten years, and for the things I did during that time. Not that I am free from sin now, but somehow I have trouble letting go of those now ten-year-old sins.