Most Helpful Guy
I think he know you like him (you told him) and he don't feel the same so he don't want to lead you on. He don't want to give you any idea, I guess.
I don't think he hate you honey. If you really want to know, just try and initiate a conversation with him asking why.
Most Helpful Girl
I think he's uncomfortable with the idea that you like him and could be staying away from you for any number of reasons- it depends how close you were before you told him. If you weren't very close, let it go. If you were really close, see if you have a chance to talk to him privately, but don't make it into this big "I want to have a private talk with you" thing. Just mention quietly that you were aware that you'd said you had feelings for him before, and that he didn't return them, and that you're okay with it and have since moved on- but only say that if it's the truth!! If you still have feelings for him, leave him alone. He's probably just not sure how to deal with it.
The safest bet is to just not worry about how he acts towards you. The awkwardness is his problem and is not your fault, and sometimes we screw up with people and we have to move on, even though we wish we could put things back into place. You never know. Maybe there's a reason that you two shouldn't be talking and you don't want to find out what it is?