You sound like a good and attentive parent

I wouldn't jump straight to changing schools, as it does sound like maybe the stress of the things you described might be getting to her. Even so, after I moved schools I hated it at first, I wouldn't go in - my poor mum, I begged her to let me change schools! The best thing she did was to not let me change, but we agreed to wait out until half term to see if things improved, and they did. If you like the school head and the tutors and counsellors, they will be really valuable to your daughter also. Maybe she could also talk to someone outside of school about the other stuff in your lives, like bereavement counsellors etc?

Adolescence is pretty intense and difficult sometimes, and your daughter is just on the cusp. Is she sleeping right, or has she started her periods?

Some schools do a good mentor scheme for kids who have troubles settling in. My school had mentors for everyone, and even though my mentor and I weren't best friends forever, her help reduced stress because I didn't have to worry too much about where the classrooms were, how to get my books etc.