Without knowing your personal details I can't be of much help, except to say that a lot of young people go through huge mood swings. The problem is when it tilts over a certain line that will affect your career prospects for years to come.
For a lot of people, life is one continuous assault course, while others seem to cruise along without a care, but you would probably be surprised at what most people go through ‘behind closed doors'. There is no right to a smooth passage, but perhaps the folk with troubles learn more on the way.
Battle against it for the moment, but if you really find that you can't cope, you will have to seek help. Your GP would usually be the first port of call.