My 12 year old is driving me, her sister and her brother absolutely insane. She doesn't listen, argues, whines (all this is WAY more than normal). She is a middle child.. her sister is 14 and her brother is 8... but she doesn't make or keep friends, doesn't do her chore, fights with the whole house. I have finally told her that she is making the whole house miserable! She's failing classes. The teachers say she is distracted easily... My hair is falling out.. what do I do??

Has she been professionally evaluated for any problems?. and I'm not diagnosing... but a child psychiatrist... might be worth a shot... don't give up on her.

I agree, child psychiatrist may be helpful. Have you tried just sitting down with her and having a one on one conversation to find out what's going on? She may feel like she's not getting enough attention (she's not the oldest and she's not the baby of the family) and that may be why she's acting out. Even if she is making the whole house miserable, be careful how you tell her that. "you're making us all miserable." can easily be heard as "we don't like you!" to a hormonal 12 yr old.