Hi, I don't know who else to talk to about this so I hope you lovely people will be able to help me out here.
DD 8 has started throwing teenager style tantrums over the smallest thing such as someone looking at her wrong, This ends up with her attempting to hurt herself by scratching herself or bending fingers back to try and break them usually while shouting at us that we don't love her and that she wants to live elsewhere as we're so cruel.
Shes an only child and she doesn't go without anything really shes not spoilt but she is treated well by everyone around her. We've tried the naughty step, we've tried time outs, We've taken privellages away I don't know what else we can do.
Tonight it all came to a head as we discovered she'd been taking the dog biscuits outside and mixing them in bowls with such lovely things as jam, We told her off especially as we had just today had enviromental health out as we have rats in our home 
she then procededed to scream and shout "You don't love me, you never let me do anything, I can see in your eyes you don't care about me!" While scratching her legs up. We calmly ignored her but she carried on and finally hit with "You won't even let me have a sister" I know she doesn't know but we've been trying to concieve for a year now and I had a miscarriage 2 months ago so this really hurt me.
I'm on 40mg of Citrolpam and have various social disorders including a history of self harm and I just can't cope with the way she is right now, I know its my fault my depression and self harm especially since there are times during my worst times that I have screamed and raged at DH that he doesn't love me.
I Don't know where to go from here and how to turn her back into the wonderful little girl she used to be who loved everyone and just wanted to help you out. I don't know where I've gone wrong and apart from leaving the home and taking my influence away I don't know what to do.