Hello, Tracey. You are a kind and caring parent, and cannot bear to see your daughter upset. She throws tantrums and self harms and you feel guity.
Normally I would suggest that emotional blackmail should be rebuffed with the contempt that it deserves. However it seems to me that your daughter's problems are something else - something more deep-seated.
I hope that the assessment from the mental health team is not too long in coming. It could provide valuable pointers.
Meanwhile, however you deal with your daughter's outbursts, please try not to feel guilty. Your daughter's actions are not your fault. You are the victim here. Do keep in touch with us about events as they take place.