I listened to lots of songs when my GF broke up with me.
I Can Do Better (Avril Lavigne)
Lots of shout-y, "I'm so over you" songs.
But what made me break down into hysterical tears was Without You from RENT (you have to listen to the Original Cast Recording, though. Daphne sings it better and more emotionally than Rosario does).
It's a very pretty, sad song.
But mostly I listened to some breakup, but some "I-can-get-over-you" songs, and screaming music, to let it all out. It helped me. So hopefully, we'll be able to help you!