I ran a lawnmower over her toes as she struggled
I hope you are joking. Why would you make things worse for her instead of helping her?
I regret doing something like that, I was angry with her just as you could see from the news.
Anger is not an excuse to do things like that. It is bad to try to hurt someone especially if you know that they are struggling!
I really don't know what I was thinking, I was really mad at her.
It does not matter how angry you feel you have to find a way to handle yourself better so no one is hurt.