Does anybody know this movie?

It was like two girls go to this private school. One is really tomboyish and the other is a girly girl. They end up having a relationship but the girly one realizes she can't be a and breaks it off with the tomboy. The tomboy girl starts freakin out even challenging the girly girl's new boyfriend. In the end of the move, she jumps off the building. I think Hilary Swank was one but then I researched and nothing came up. thanks