Anger issues help how to prevent?

As some of you may have read before, I have had a hectic and depressing trauma. I am very depressed and I find I have very very bad mood swings. A few months ago me and my ex broke up. We are very good friends still and we love each other as best friends. However because of these mood swings he seems to be one of the many people who get caught in the middle of my behaviour. I have a really bad anger problem and today he kept spreading a rumour. I know it was just a joke but something overcame me, and Bee overtook me and suddenly I spazzed and completely freaked on him. I managed to hit him really hard. I don't feel bad at all. I just wanna know what's wrong with me and how I can prevent this. It was really bad rage... Help...