What is clear at this point is that your daughter has begun to have sex in an unhealthy manner, now having slept with three boys (it could be more) since she has been on birth control pills. Sexual promiscuity in female adolescents is often a sign of depression or low self-esteem. She's not having sex as part of being in a deeply committed relationship. Instead, she's caught up in an unhealthy behavior that also demeans her. Although she will protest loudly that there is nothing wrong with what she is doing and that you can't stop her from having sex, you need to get her some professional help.
My bet is that behind that anger is a frightened girl who needs some compassionate support. I know that you feel helpless regarding your inability to stop your daughter from hurting herself. Believe me, your daughter is out of control and your job is to love her, to stand by her even in the face of her anger toward you, and to get her the help that she desperately needs. I'd also suggest that you read Venus in Blue Jeans: Why Mothers and Daughters Need to Talk About Sex, by Bartle and Lieberman. Let me know of any progress.