My girlfriend left me about four and half months ago but i still think of her all the time. I have a very deep depression and have serious problems at sleeping (damn, haven't even really played since) She slept with other guys for possibly over 10 times and i didn't know about it, she lied about where she was or was going but we still loved each other and had the greatest time of our lives together. We travelled together and did some amazing things, things that'll stay in our hearts forever im sure of that. After she dumbed me, she went to a bar and started to hump all the guys and after a week she was dating someone. Still getting drunk every week because of her...i could kill someone just to see her once....
Well, this is my "bitch in life"
The only thing I can tell you, from similar experience, is that time will eventually give you the wherewithal and alacrity that seems so unreachable right now. Just remember that even if things look bleak in regards to your break-up and her attitude, you had a positive impact on her life and she on yours, and however brief your "good" time was, it deserves to be remembered fondly. There isn't just one person for one person, that's bullshit. There is a whole world out there full of pained souls and bruised egos who deserve a second chance. Take what you can and embrace whatever comes tomorrow, and remember that you will love again and you will hurt again, and it will all be beautiful because you are alive.