Do you think that he just used me for ?

I'm not sure what his problem is. I can't tell you if he used you for or not, but I can tell you that he is a genuine jerk. You are being entirely too nice to this guy, who is being a complete **** to you and is quite obviously not telling you the reasons behind his actions. Do not waste your time even trying to be this douche bag's friend. He doesn't deserve even your friendship. I would completely cut all ties with him and not look back.