Should I be concerned about my daughter? Or is it the big "P"?

I'd probably just keep an eye on her. maybe it's her way of letting you know she needs more one on one time with you. If you start to worry perhaps take her in to the doctor for a check up. At eight she still seems kinda young but like you said it has come a bit early before. I'd just keep an eye on her for now. It could be something is going on at school too. Other kids can start being mean and agressive around that age. good luck