Strong feelings for someone who doesn't love me back!?

I really like this guy, who's in my same grade. I always wear cool clothes and makeup, and I try to be at my sweetest personality when i'm around him. Trouble is, he likes this other girl. He likes this other girl A LOT. And that other girl, is my BFF. I have another BFF and I told her what happened and how I feel. She said she felt the same about another guy, and now they're together. I want that to happen, but somehow I doubt it. The guy I like is really close to my BFF he likes, and my BFF he likes seems to like him too. I get so jealous when I see him wither her, I can't control it. I stopped focusing on school, decreased practicing piano, and my grades took a dip. My friends think I'm weird and all-the-sudden-dreamy, and I'm in a total trash state! I really passionately like this guy! When he walks by, I don't know if i should flutter inside or punch him in the face. I feel like both. I really like him, But I know I have no chance because they like each other. I'm suffering from depression that can't really heal until I know he has feelings for me, which he obviously does not! I really want to get over it, but a whole chunk of me needs to be with him. HELP!