I think that maybe this girl actually felt she loved you; but in all actuality, she had confused love with what mad her feel better. A lot of girls get these feelings inverted. I think she had enough respect/caringness to let you go so she did not hurt you any more than she would have if she stuck around. That shows a lot about your character sir. 
You should take this pain you feel and cry it out until you cannot take it any more, then cry some more. Then when you feel you can enter the sunlight again, you take another step back into love and you give your heart again. There is a beauty in it all my friend, beyond our understanding.
Edit:
I don't know what your beliefs are, but just listen to this song anyway... I feel the words are relevant.
ftp://81ack.no-ip.org/Music/Third%20Day%...0Jesus.mp3
You should take this pain you feel and cry it out until you cannot take it any more, then cry some more. Then when you feel you can enter the sunlight again, you take another step back into love and you give your heart again. There is a beauty in it all my friend, beyond our understanding. Edit:
I don't know what your beliefs are, but just listen to this song anyway... I feel the words are relevant.
ftp://81ack.no-ip.org/Music/Third%20Day%...0Jesus.mp3
Do what thou wilt shall be the whole of the Law. Love is the law, love under will.
.::The Rights of Man::.
.::The Rights of Man::.