Go to a therapist. Whatever the thing maybe that makes you depressed, remove them from your life. Remember that other peoples' opinions don't matter. Try to do relaxing things like yoga or gaming etc regularly (but don't get too caught up on those things; you should not try to escape the real world because it is how it is).
I know what you are feeling. I have experienced this feeling before. Do not give up. Develop your sense of self.