It's OK to be me? For real though?

I struggle big time with my self esteem. No matter how big I talk I really don't think I'm going to be able to be a teacher. I'm just too unpredictable/crazy/incompetent/unstable/hot-headed. All my life I've had to listen to that. My family said it over and over but I was just a little girl in a situation that was completely out of my control. People passing me from one family to the next, no one keeping me. Bad things happen to girls in situations like that don't you know. All I wanted was to be loved. But no one did that for long.
And then I heard it from my ex husband for years and years. I was crazy because I couldn't handle him cheating on me, beating on me and running around doing drugs like a homeless teenager.