Since you are asking this question, I assume you must have been pretty interested in this individual. The fact that he has not returned your calls, shows not only that perhaps he is no longer interested, but that he is not man enough to let you know that he is no longer interested, if that is in fact the case. You have only known him a couple of weeks, so do not let those few weeks cause you to be down on yourself, or feel that it was something you did. He is probably the one with the problem. I would suggest you not to call him anymore and go on as if he never existed. Do not waste yur time even wondering what happened. Afterall would you want to be in a relationship with someone who cannot communicate their feelings. Life is too short to worry about other people issued, and it is clear that he has an issue. Their are billions of men out there and to let just one have you second guessing yourself is not worth it. I do not know you, but if you are the type of person to fall in love quickly, I suggest you try to control that emotion and view your dates as casual dates until a commitment has been made. That way your heart is not invested when they do not call and you can easily move on.