When he sends mix signals

I work with this boy and we were close friends. No day went past without us talking...we felt really comfortable around each other. However, feelings got caught and he made it feel like I was the only one confused. Now he ignores me and treats me cold at work not even looking. I asked if he had a problem with me but he denies it. Also, he makes it clear that "I'm not his type....but I know him and I'm not sure if he is fronting or he went cold on me. I got him fews times lookin but when I look he looks away quickly.