WHAT DOES IT MEAN?! does he really like me?

There's a boy that I have a big crush on and once he talked to me on msn and told me that he liked me. I kind of knew it as his conversations were always funny and even when we meet he would be like kind of protective on me. After that we met again and he didn't behave like before he was more quiet and even sometimes he ignored me. When I talk to him online sometimes his conv are like before and sometimes he turn quiet and like he don't care. Last week he told me that he was looking forward to meet next time we go out but when we went out he was with his friends and I was with mines and he only smiles at me ( a lot )and he never talked to me. Did he changed his mind??? what can I dol? hlp me pls