My advice is to sit down with yourself and decide what do you really want, in this stage everything is possible.
You can "move on", I am pretty sure that much better oportunity is waiting for you, just around the corner, but you have to move yourself to that corner.
Second option is to use this situation, learn something and set some new rules with relationship with your ex GF, but you have to be very, very strontg to pull-this.
I would say that your ex GF is quite a mess, so you have to be strong and bring order to your relationship, even if you stay only friends.
If you decide to go with this second option, I would sugges t write her a letter, write that you trully care and want her to be happy. That you will be glad to stay friends wtih such beautiful person like her, but you need her to give you some time to recover, so you will call her in month or two, ask her to be patient.
If you carry on with this, and stay strong she will chase you and you will never have this problem again.
Good Luck