Struggling with Anger: How to Control It?

I'll have a great time then all of the sudden my anger gets the best of me. I try so hard to hold it in and not let it explode out of me but it happens so much and so intensely that I don't even know what I do or say until after the fact. like at work I had my boss give me a really hard time about things out of my control and was very unprofessional with me. it took so much engery and will power to remain calm but it felt so burning inside of me I almost left my whole job today in a rash choice. I need to get my mind off of it somehow without getting mad but it is so hard and frustrating that I can't even control myself then thinking that makes it harder and I just get madder and then over thinking just makes me more upset it's just a never ending cycle of angry misery