I'm really and I'm really sorry for asking this but ... how do I stop being so mad at someone for what they did in the past?

Answer: you should forgive the person even though you are mad. We're all human we make mistakes everyday. it's going to be okay I promise.

Explanation:

Nearly everybody has a bad past. Some wants to forget what happen. It's better to forget then holding in a grudge. the more you hold it in, it will hurt sweetie. Always stay strong no matter what.