Let me ask you one thing first...are you fully aware that you are behaving differently at times? if you are then i see you have already crossed half the bridge.
It appears to me that your studying as well as working is taking toll on you. So first begin with taking things one at a time. prioritize your things. make a check list and work accordingly.
begin your day with some form of meditation
so that you can have a relaxed and active day. include exercise and healthy diet in your routine.start seeing objectively why you feel angry at people or the situation. try to see the positive side and try to find solutions rather than holding grudges.
if you still feel your behavior is out of your control you may need to see a psychiatrist
or a counselor.