I've become good friends with this guy I work with lately. We hang out all the time, talk all the time, and seem to have a good time from what I thought. He's been borderline flirty with me a few times, OK when I first met him he was REALLY trying to flirt with me. He has a girlfriend but it's long distance. I've never flirted with him or made any advances because of her, even though I want to. Now, within the past 48 hours, something has happened that he is barely giving me the time of day but being perfectly normal around all of our other friends. I've done nothing, so why I am getting the cold shoulder?