Why has he done this to me?

take a couple of girls and go guy hunting :D its okay to be a bit of a flirt as long as you dont do anything then its a rebound. really when you get broken hearted you want that feeling that someone thinks your pretty and that someone loves you. well getting picked up by guys is a great way. unless you are really interested i would not advise to go on a rebound. hang out with girls. and do things you love. get all that pain out and confront yourself that he is a player and he doesnt deserve you. you deserve a lot better so find it! be true to yourself and dont let his foul mistake of leaving you in the dust get you down!