Could he like me or am i over reacting and making things up?

late last year this guy (for now lets call him Bob) looked at me in the corridors sometimes, and sometimes it seemed like he'd half smile. it wasnt all the time though, it was just sometimes. but he didnt seem to do it to anyone else. he stopped doing, at least i didnt notice is much, this year, except recently, he kept looking at me in this room with a lot of people and i think he smiled. im pretty sure he smiled. later on he put his leg on my chair randomly and seemed to be around me a lot... and now he sometimes looks at me in the corridor- but not always, only sometimes. hes the type of guy who goes for good looks i think, and hes the hottest guy in the year (although he is shy and definitely not popular). hes friends with this really pretty girl and i think that he'd like someone like her- shes gorgeous and a lot of guys used to or still do like her. im not ugly but im not hot, i dont think he'd like someone like me anyway. i think im over reacting but i just need to make sure.