Mental illness. Get back in normal life?

He can't concentrate on anything.recently he had a break up and her mom cut off relation vd him and many more family issues.since childhood his parent's got separated.he completed his studies on residential school n then he started living in separate home.He is depressed somewhat. He feels like living alone, not talking to anyone, fly away to a unknown place.he is doing M. sc. his performance in study is deteriorating.he can't concentrate. He can't even decide his carrer plan also. His mind isn't stable. His past is haunting him. He feels like everyone is going to leave him whom he loves.this thought is haunting him like hell. now he is scared of getting close to anyone.. He is not able to find peace anywhere. In dream also he gets scared.what should he do to get back in normal life?