Does this guy like me and what should I do if he does?

Im 17 and theres a guy in my class I like called nick, the class hasnt started long and when I first met him I thought he was flirting with me but I kinda shrugged it off and just thought it was in my head but then a couple of lessons after that he started stareing at me, like realy noticable so 1 lesson I said to him what? and he said what? back and I said your stareing at me and he said he wasnt but he obviously was, I only chat to him a little, when were on our own, hes always joking, we play fight too lol he just started messing about with me one day lol I was chatting to him the other day and I had to move seats and he was like dont leave me lol the problem is I cant tell if he likes me for definete or if hes just a joking flirt, do you think he likes me and what should I do about it??? I realy, realy like him but I dont think I can have him, sadly :( xx