I slept with another girl behind my girlfriend's back.
Why did you cheat on her?
I was angry and I wanted to get back at her. It ended up getting me into trouble, she never did anything wrong to me, it was all my fault.
It sounds like you regret your actions and know that what you did was wrong. Have you talked to your girlfriend and apologized for cheating on her?
I've tried but she won't talk to me. This is getting harder and harder.
She's understandably pissed at you, but you need to keep trying if you want to save your relationship. You dug your own hole, now climb out of it.