I don't know what to do?

Corniest line you will ever read...but I'm in love with my best friend. Whenever I would read that I would just laugh. Karma got me. He's my best friend. I tell him more than I tell anyone. I'm 17 and I never really like him before but he's just so amazing. He's all I think about...it's pretty unhealthy, but I can't help it. I try to get myself to not text him for a full day and it's so hard. I don't like showing my emotion if I like someone. So I try not to make it obvious. But I'm head over heals for this guy. He's amazing. Whenever I'm sad or depressed which has been a lot lately he always sends me songs to listen to. He's so patient with me even though I can be really annoying and I let a lot bring me down. I can complain to him and he always listens. And it's the other way around too. He can tell me anything and I love to listen and help him out. I can't help but go out of my way to do things for him. He makes me so unselfish. It makes me so happy to help him in anyway I can. I don't want to feel this way, but I do. I don't know what to do about it. We've known each other for a long time and I literally know everything about him. Sometimes I also feel like he's way to good for me. I don't know anymore. Advice? Thanks!