Is it normal that i can't stop thinking about my teacher

i have this teacher that i can't stop thinking about. i've had three classes with him and i've heard him talk about music, tv, sports, etc and we all pretty much like the same things. i have lots of dreams about him and i know he's married it's not like i'm in love with him i just cannot get him out of my head and it's killing me because i'm so shy and i blush every time i talk to him, is this normal or is it obsession i can usually tell when i'm obsessed with somebody but i can't tell?