Matt-Page said:Why can't i let go? Why am i so eager on trying to win her back?
In my opinion its to do with having some structure, some familiarity, something solid in your life. She WAS a major part in your life for a long time, and as a result it will feel odd to not have her there anymore. You just need to remind yourself that there will be someone else out there who makes you feel even more special/loved/wanted than your ex ever did, and that one day (perhaps not soon) you will feel 100% content with who you are with at the time.
Its hard, and most of us have been there at some point, but you HAVE to move on, if not only for your own sanity.
Perhaps you aren't actually 100% satisfied with yourself, do you feel the NEED to be with someone, or that you can't be truly happy on your own? If so, perhaps take a step back and take a look at your own life. You may find that you are missing something from your own life that makes you happy about yourself, and when you find it, you will be able to find someone who loves you for who you are, and not loves you to fill a hole in your own personality.
Go take up a new hobby, something to occupy your mind! I took up rockclimbing last time I split up with an ex, did me the world of good!