I can't concentrate on anything. I feel like I'm in a coma (cuz schizophenria I think?) I don't understand anything with my brain. I am lost.

See psychiatrist. At 17 years of age feeling like lost , can not concentrate may be some problem at school or home and problem with friends may be disturbing you.May be you are depressed and unable to understand. Better consult your doctor -psychiatrist and explain your problem.