There's this guy who I am 99% sure likes me, so what to do now?

I just started going to this school and I work in the library there too. There's this guy who looks to be around my age 20. I fist saw him a couple weeks back. We kept giving each other eye contact over and over again while he was in the middle of a conversation with this other librarian. Then he was in a cl in the library doing a presentation and we kept giving each other eye contact throughout his presentation. LoL! I know bad idea to make him even more nervous in that type of a situation. Anyway, he comes and sits in this chair near the front desk of the library where I am working. I was finally convinced he was gay when I saw him talking to this flamboyant campy guy in the hallway. Today he came back in the library and he ped back and forth a couple times smiling at me. Before he left he said "have a good day." I say "u too!" He says 'Thanx" I say 'ur welcome' I only see him when he comes to the library and I think it's inappropriate to ask anyone out while working tho