I was SO SURE my dad was going to support me when i told him he had to make my mother move out because she was always mean to me. It was quite a surprise when he informed me she was a member of the family and that she would be staying. I had assumed she was just a lodger. But i think she backed off after that.

Isnt this the oedipal phase? Combined with teenage phase of hating the parents.

So - she doesnt want to hear bad news from you, like no school.