So this guy has been extremely nice to me for the past few weeks and he goes out of his way to help me and always cheers me up. He always sat next to me whenever he could just to chat. It was kinda obvious he was into me and all my friends kept telling me he liked me. Lately however, he's turned into a real douchebag and has been acting extremely mean to me for no apparent reason. I actually got really mad today and hit him :X (not hard!) So what's the deal with him?

Most of the guys who liked me or something before always said something or just acted like he likes me but why is this one acting like this?

maybe he's upset because you did somehthing wrong or he heard a rumour about you? just try talking to him alone and ask him what the reason is to why he has been acting this way lately, if he dosent let you talk to him, try writing him a letter and keeping it in his locker or desk.