Talking. When a lot of tension / pressure / stress / frustration accumulate inside, there can be unexpected outbursts of anger that can be quite frightening for all who witness it. My guess is that having an opportunity to talk to a close friend or a professional about whatever is troubling you will afford you tremendous relief.
Anger. I would recommend to see a professional. Could be a psychiatrist or psychologist. There are many questions that need to be asked: how severe are the anger attacks, how frequent, are there any triggers, how is your baseline mood, do you use any substances/alcohol etc. Anger could be part of a variety of medical and psychiatric conditions.