Am I depressed or stupid?

I have had seeious trouble sleeping, tossing and turning all night. I have had a shitton of cravings and am eating alot, but am not gaining weight. I sometimes get these moods, that last a few hours, that make me feel amazing, though most of the time i'm easily angered, out of energy, tired, unmotivated, pissed, sad, and pissed. I do not have unexplained pains or aches. I have thought about, planned suicide. I wrote a note, but can't actually do it. I have, most of the time, a shitty self confidence. I am stressed out alot most of the time. I try to avoid contact with my family, but don't mind strangers or friends. I often do really stupid **** for noreason. I only drink or use drugs very occasionally, like once a month. I'm 16. I am a male. No current relationship. No recent traumatic experience, last one was 3 years ago when dad died on my birthday. No diminish in sex drive. I don't see a change in my mood in different seasons, but i have an awful memory and can't recall feelings at all and can rarely remember scenes. No prior history of depression or other mental illness in my family. I have a history of cancer and serious addictions if that means anything. Thank you very much for your help.