Why won't any treatment work against my depression?

I've been dealing with this bullshit now for 8 years since i developed post traumatic stress from cancer at age 12. I'm turning 20 in a few weeks. which means i've been depressed for 2/5 of my life. I have have been on every anti-depressant, mood stimulants, anti-anxiety, attention deficit medications. Nothing helped me. I was on anti depressants for 3 years and never saw a change in mood. I have been to years of out patient therapy, 1 year impatient therapy. I spent 1 year revamping myself (got into shape, got a rhinoplasty hoping i could rebirth myself) When I got to college, I fell back into heavier depression. I don't leave my dorm room, i have no friends, i cant concentrate, im always existed. My family now seems to busy and lost int rest in helping me. Guess they just gave up. If i wasn't so apathetic on everything I would have killed myself already. One of my regrets are that I didn't kill myself 3 years ago.