7 year old DD's behaviour is out of control and I am at a total loss. She answers back, is cheeks, questions every decision i make if she doesn't agree with it (and i mean questions it x 100 while stamping feet / throwing herself around like she is having some sort of fit). Its absolutely exhausting and I dont know how to sort it. I have sat down and spoke to her and she always says she'll behave but the next day she is the same old. At school she is a star pupil so this behaviour is for my benefit.
I am totally open to the fact that I have soemwhat failed in parenting to let it get so bad and am willing to put effort it to resolve it. I could actually cry, my whole weekend has been consumed with her misbehaviour. The 2 younger DCs are seeing her behaviour and are definitley pickinh up on it.
I would be really grateful for any advice.