Why is my best guy friend avoiding me?

Ok so me and him have been friend for a while we met at the beginning of the school year through a friend but then we started to hang out more and sit next to each other at lunch (we don't have any clashes together except for gym)and at the time it was the getting to know you phase. Any ways we used to talk every day non stop even though he has a girlfriend.(she's super nice) then one day he wanted my number so I gave it to him then the next day he completely ignored me all day at the time I thought he was just playing but then he didn't talk to me the next day and it been going on for about 1 week and I don't understand why he's doing this! He talks to all my friends when im around them but doesn't even look or talk at me. Every one in a while I will catch him looking at me a couple of tables across from me but I'm not sure if he's looking at me or my friends. I'm really depressed and geting sort of worried that he hates me. Please help!

Maybe his girl friend said something but didn't want you to know, Like he should not talk to you as much because she's jealous. But what I think is he probably likes you and just now realizes it and so he could feel awkward. You should just try approaching him and talking instead of waiting for him to come to you. And if he ignores you while your talking to him . . . then I have no clue what you can do, sorry but I never had stuff like this happen to me.
HOPE THIS HELPED A BIT :]