Someone very wise once told me that doing something bad does not equate to being a bad person.
Since you are no longer doing things that you consider to be "bad", then perhaps you can move forward from this.

I have mentioned this before....I'm a big believer in atoning, or doing penance for my past bad behaviors....Not in any kind of radical or even related way....
I simply try to do something good in an other area of my life that I wouldn't normally do. Perhaps buy lunch for someone less fortunate than myself. Or donate to the women's shelter.
I realize that we should do these things anyway, but I try to keep in mind why I am doing them.
It doesn't erase the past, but it does help me feel better about myself.