Dd is lovely but has been violent since she was about 7 starting with pulling down curtains in rage and throwing stuff at me and DH (her dad). She can be fine one minute then fly off the handle (to be fair I don't have the best of tempers) BUT sometimes she attacks us. Her attacks were less frequent but she is now in year 11 and is very stressed and clearly reacting badly because of this, shes virtually shouting all the time! And attacking us more.
Recently when Dh was explaining her brothers math problem to us she ended up escalating to the point I had to go to minor injuries go get dressings where she stabbed me in the leg with a pen! The minor injuries said social services would get into contact but its been over a week...
She says she feels awful all the time, wants to kill herself (this is not just around arguments though so I dont think it's always related to fishing for sympathy and sorries) and asks us not to talk to her but even asking her to pick up a plate makes her angry. We have asked for help with how awful she feels at doctors and shes asked at school to be let off art gcse to ease school pressure but they need a doctors note for any health issue but doctor says it is a school issue 
then school said she just has to do it but they could help with a self referral to camhs (but not refer her themself- I had been under the impression they would do that). School don't really know about her at home aggression.
She seems to feel a lot like people who are supposed to help her are letting her down. She says school won't listen to her, doctors won't help, and I need to get involved more.
It's awful and I dont know what to do anymore, it's so hard for me to speak for her I never know what she wants me to say.
What do I do?