Why do i feel s randomly depressed?

To me it sounds like major depression it includes being depressed, irritable, and sleeping patterns will change some people don't sleep.. there's more to it i just don't know everything but i have it myself and my advice to you would be to go see a doctor and be completely honest with them about how your feeling, if you having thoughts of hurting yourself you need to go sooner they will not think your crazy they will just get you on stable medacations to make you feel better