Going Crazy

I am going absolutely crazy nutters insane!!!
I don't know what to do about my kid, she is doing a bit better today. But last wednesday she got suspended from school for throwing salad on another table of girls and she refused to clean it up and then went crazy and had to be restrained and she cussed and fought the security guard and the police officer who works at the school. She went back to school yesterday. She had to write an essay about why she was ready to go back and all that and that she would do her classwork etc. and that she wouldn't freak out anymore. She has new cuts on her and I just don't know what to do. Then my youngest lynnie, comes down and informs me that Pan asked her to hump her. Then later the next day Bellie and lynnie both came down stairs and said that Pan was flashing them her private parts. What the FUCK am I supposed to do with this child. She flat out refuses to go to a counselor. I just am at a loss. I feel that things might get worse and she might be a threat to her sisters.
She hits them all the time. But worse is the sexuall stuff. That really really bothers me. I don't want to send my daughter away because I don't want her to feel like I don't love her. I don't want her to feel abondoned. But at the same time I feel like I need to protect my younger girls . And I feel like I am a terrible mother for wanting to send Pan away some where. I have no clue where. I have been told that I need to call cps and have her go to foster care for sexually agressive youth. Thats just it though, she's not agressive. She has issues. She hurts herself and everyone else. She will just walk up behind her sisters and smack them HARD for no reason what so ever. I was the oldest sister and I tortured my little sister but never ever did I HURT her like Pan has hurt her sisters. I don't think its normal and I hold that it is unacceptable in my home. I don't know what to do. I don't know what to do. I don't know what to do. I am spinning in circles of hopelessness here. WHAT THE FUCK DO I DO?????