this not is not a problem to be worried at all.but this is not normal.
try to following things in your life :
1.Keep all your stress
and worries aside.
2.believe in the fact life is to enjoy.
3. try doing meditation
daily for half an hour.
4. i think there is some thing that is bothering you all the time. if so try not to think about it.
5.make true friends, spend time and share with them.this will keep you relaxed and engaged.
hope these will help in solving your problem.