Bellaz, I can tell you that when I like someone, for instance, I have a tendency to act distant and avoid eye contact altogether. People that I've fancied in the past, (after finding out) have often said that they never realised and thought quite the opposite!
It could be that he is attracted to you and is uncomfortable about his feelings because of other factors involved (his position in the department,has a partner, etc) I'm just putting the attraction hypothesis forward as a possibility. You never know, and it could be that you'll never find out. I wouldn't know how to resolve this. I guess you can't just come out and say: "Hey, guy! Do you hate me or what?!"