Look within yourself, to see where your anger is coming from. It may not actually be about your friends.
All behaviour is communication,. often anger comes from frustration, either temporary, or deeper, such as maybe you think you should be doing better somewhere in your life?
Some anger comes from past trauma that is unresolved. If so, you may need to go to counselling.
If your anger is really bad, maybe go to anger management classes.
Also, sometimes adopt a different perspective, somethings aren't really worth getting angry about.
Anger is bad for your health, heart and blood pressure.
Maybe you are hot headed, with no real reason to be and a learned response, in which case, cultivate an inner state of calm. Maybe try getting out into nature, or any activity that puts you in the moment, or try yoga.
Maybe you are using your temper to try to control people, to get them to do what you want?
Only you know, look within for you answers.