Was he even interested in the first place?

[cass93]

There's this guy that I have one of my college classes with once a week who I really like. For the last 9 weeks I have felt him stare at me in class and sometimes we would have eye contact or just be looking at each other (I always break the stare though cause I get too shy). Last week when I was leaving the class I turned round at the door and he was staring at me and then I walked passed him a few times in the hall, while my head was slightly turned talking to my friend I saw from the corner of my eye he was looking back at me (I had a feeling cause I didn't look back at him looking back at me last week I might have blown it and missed my chance) I walked past him again a few minutes later and the same thing happened (Although he might have looked back the second time because I was singing and clicking my fingers like an absolute moron..)
I have talked to him once before (we were put in a group to do work one day and I felt like we had a connection...we had been staring at each other from across the room before we were put in the group) but I can't figure out if it's cause of that or if he could be interested. Maybe it’s just because he has noticed me looking at him.
Today he didn’t look at me once. I sat opposite to him on a computer and I got NOTHING... I actually feel kinda sad about it. I don't think he is shy because he doesn't seem the type and he has absolutely no problem talking to other girls in the class. I tried staring at him today but he didn't look once. Was he even interested to being with? From his twitter I can see that he is not short of female attention. I just don't understand...any ideas?
I have seen him looking when I was walking with my guy friend...