Help me identify this song, Please!!

I've heard it on the radio a few times, I'd describe it as eithe R&B or hiphop, and I've only caught bits of it while flipping stations because it isn't really my thing. I don't know the artist or name, and a lyrics search from what little I can remember doesn't turn up much.

It is about a girl named Rain (I think) who was given up for adoption at birth and mis-treated by her family, and at the end she is standing in the rain and I think she commits suicide.

What is this song?!?