crush problems please help!!?

I liked this guy for about 6 months now. He likes me and I like him. His friends told me. And my friends told him. We know we like each other but never told each other how we feel .And I don't know what to do. We use to talk and flirt all the time. Now we just stare at each other. And have small friendly talks.. He stares at me ALOT. Everytime I turn around he's looking at me like he wants to talk to me, but doesn't. We talk last Thursday. It was friendly small talk... Cause I was with another friend. I really want to tell him how I feel before its to late . I don't want him to lose interest in me. But I can tell its happening. I messaged him maybe 2 times on Facebook. He always replys. But never messages me first...? Which is werid. He's rarely on Facebook . I just need advice on what to do. He acts like he likes me. Than there's signs he dosent. Its like he's confused himself . I just want to tell him how I feel and ask him if he feels the same way. I barley see him at school I had summer school with him . so I might just tell him on Facebook before its to late. What should I do? I don't want to give up. :'( its my fault. Im way to shy around him and scared. I think he's getting annoyed of it. We could of dated by now but I ruin everything. We always are mad at each other over stupid things for example "why are u ignoring me?" Or " how come u don't talk to me anymore". He plays the ignore game with me. As far as I know were friends but I want to be more.......