The Power of Self Forgiveness
It is time you freed yourself. Tell yourself,
"this is me, I too can get malicious, I too can get evil. And I know I did. I can't quite know my objectives then, but it happened. And I forgive myself"
There is no such relief that comes from self forgiveness. It frees you. It makes you feel anew. And most of all, it makes you grow, accept yourself and even learn to appreciate other peoples weaknesses. So find the person in you, and sit them down, have a self dialogue, and you will have broken the chains of guilt in you. Deal with the one you wronged later.