I really like this guy I see him every day at high school. I've never been in a relationship before, also I don't want to get teased if he says no. Before the summer holidays and at the start of this year he kept looking at me but recently not so much. I've talked to him once one Facebook and he was really withdrawn with very basic awnsers such as 'lol' and 'kl'. Also in one of my lessons with him he's was talking to my friend and she said I liked someone and I think he may have been a bit shy but it may just be me? We talk a little bit but only in lessons.
Please help I'm confused.

There is only one way for you to find out. You are going to have to do something really daring. You are going to have to ask him to do something with you. Go to a party, to a game, to some event. Try to to pick something he would never go to because then you won't know if he said no because of you or the event. Alternately you could just be in his way as much as possible without becoming a speed bump. Say hi ask him how he's doing every time you see him. Try to think of one simple question you could ask him when you see him that might lead to a conversation. Good luck!