Loss of interest in life. Lot of times.

I have been very sad and lonely for a few months now. I don't really have any real friends that I feel I can rely upon. I am always tired, but either I sleep the entire day or I don't sleep for days. I don't wanna get out of bed, or talk to anybody. Every person seems meaningless and fake to me. I easily get over emotional and super sensitive about tiny issues. Even the slightest thing makes me very very angry. All I do is cry all day. Most of the days I just feel empty, but I worry a lot. Always under stress. I used to have an excellent memory but I can hardly remember anything now. Even my appetite goes all weird at times. Either I eat a lot at times, or I starve myself for 2-3 days. I shamefully admit of trying to have harmed myself a lot of times.