You have, very interestingly, stumbled into what anthropologist Rene Girard coined "the mimetic triangle." You're going to lose all the power in this dynamic in a few weeks. She doesn't really like you, just the drama.
I would extract yourself from the situation with her, allow yourself a confidence boost from the hookup, and direct your focus on other girls.
I would extract yourself from the situation with her, allow yourself a confidence boost from the hookup, and direct your focus on other girls.