Im always depressed how can i fix it?

all my life I am a failure. My goal is to be a NBA player but I never feel like the best, the coach puts me as a benchwarmer. No matter how much I practice I will never p, I always fail. I practice basket 5h a day and I still suck. I can't concentrate on school cause I feel like I haven't finished my goal. It feels like I'm such a loser. My dad says you live in a dream world and you need grades. The problem is that I don't want to be a normal person. I look at TV and music videos it feels like my life sucks. I thinking of dropping of school to go to a private basketball coach and train instead of school. I thinking not getting noticed in school but in AAU.HELP!!!!!!!