How do i get back to normal?

A guy made me fall in love, but he was just playing. I fell in love with him deeply. Even after I realized that, I just can't get him out of my mind. I feel very depressed and can't do anything the right way. Because of him I also was acting weird with my friends and my friends kinda started hating me. I mean I'm not sure, they were being moody. Now it feels like no one gives me much importance at school. My life is weird. My grades went down and my parents r mad. Everything in my life went down becuz of him. i'm soo mentally disturbed cuz of him. Now it's summer. My friends r on vacations, some are busy with summer school, and some are grounded. I have no one to hang with and I feel depressed. I really loved him and I feel very suicidal right now. It's like i never get to talk to him ever again in my life and it hurts so much. All those sweet things that happened with him r good for nothing now. he deleted me from his life, he deleted me from his facebook. Why did he do this to me? I feel suicidal. Help me please. What can i do to get things back to normal?