yeah, what they said. dont worry about things man, i know that a break up can be one of the most disturbing things that you can go thru in life. a significant other is someone you confide a level of trust in that no on else holds in your heart. any time that you have something happen with them, it hits home, because they are the one you think would be there to back you up. as long as you keep your head up though, nothin that happens to you can hurt you too bad though. you can look back on prior relationships and see them as a learning experience. you can think of all the good things that have happened and say that you had a positive effect on the other persons life. hell, you might even look back and say you were the best lay that person's ever gonna get, and they dont know what they just gave up.
As long as you allow yourself to have some hope as to your future, then nothing can ever drag you down. and if you are really feeling like she ripped out your heart, screw her best friend. j/k, j/k!! lol. well, like i said, just look for the best of things that have happened man. you will be the better person in the end.