We text and talk on fb, but in person it's like I don't exist?

[xxLiVeLAuGhLoVexx]

I think this guy is quite cute and I finally got to meet him at a party and we ended up talking and hanging out the whole night, I even gave him a ride home to his house. Now we talk on fb and he pretty much asked for my number (he asked if I have a phone) cause it was apparently annoying to quit out of the game he was playing when he got a message from me (he was on fb with his phone) so we texted last night and he's a really nice person and seems like quite a gentleman we like the same show but have very different taste in music. Anyway, when it comes to school, it's like I don't even exist? There's only one class we're both in and he doesn't look at me and there was a chance he could of sat near me but he didn't (maybe I should of invited him?) I noticed him today right beside me at the cafeteria and I said 'Oh hey *name* ' and he just said hi, not very happily at all I think.

He is a Sagittarius and I've asked his friends and people that know him if he's shy and it doesn't sound like he is, but you never know.
So what's up with him? is he infact shy?
oh btw does he act weird in person with me because some/one of the boys could of told him I thought he was cute (seeing as I did say that to some of them) and some of the boys asked if he liked me and he said no. But of course he said no he hardly knows me.

So yeah, do you think he's interested? and why does he act like I don't exist in public, yet we talk like friends through fb and texting

thanks