Anger is an emotion that pops up when your expectations are not met or during helpless situation etc. This isn't a bad emotion as far as you are able to understand and manage anger and direct your energy towards productive tasks and not to destructive ones.  You can challenge yourself at such times to achieve something; as simple as accomplishing preparation for the entrance exam. Talk to people, be your self. When you talk out you will feel much better. Learn to balance everything in life. Lastly ensure you sleep for atleast 7 hours continuously. Perhaps you may not be good at managing time and work. That must be irritating you and you get angry.