DD is 8, and still, about maybe once every 10 days has massive meltdowns when she shouts, screams and is incredibly rude. She is often quite rude in between, and the meltdowns are often precipitated by her being disciplined or told off for this (or told she can't do something she wanted to). She is polite and well behaved at school and outside the home. There are some fairly low grade school friendship issues (not bullying) which I think make her unhappy and while she comes across as happy and confident I think she is actually the opposite. She is very jealous of her younger sister.
I've tried to get her to talk about her feelings so many times and really got nowhere, and also try to give her regular 1-1 time away from her sister, which she loves. I just don't know how to deal with the rudeness and tantrums - this morning she was awful and we actually ended up cancelling two activities this week which she enjoys. She's then very contrite (mostly because she want the punishment revoked rather than genuine repentance) but we will obviously be following through.
She obviously can control her behaviour to some extent as she doesn't do it outside the home. I keep trying to explain it's alright to feel angry, but not to behave like this. Are we doing the right thing by getting tough? We do cuddle her etc. afterwards but this really can't go on. This has been going on now for about 3 years so not recent (she wasn't a tantrummy toddler) and it wasn't precipitated by anything obvious. Interestingly if she kicks off in the morning she always manages to calm down by the time she needs to go to school as she realises we would have to explain her absence to the teacher.
Any advice would be very welcome.