Hey, i think this is great. i have the same problem, my best friend ditched me for her girlfriend... my favorite part was the last part:

A b.i.t.c.h. like her,
deserves a b.i.t.c.h. like you,
So really darling,
Your backstabbing me was a favor to do.
Let me leave it now,
I guess I expected it all along.
It's just another backstabbing friend,
in my life's story,
as it goes terribly wrong.

i liked it. good job!