Oh Rosetti Big hugs

You haven't failed her. We aren't expected to know everything that's happening at school, especially without any communication from the school. Failing her would be doing nothing about it now that you're aware.

What did the teacher suggest as a way forward? Or did she just say "this is the problem" and nothing else?

What do you feel might help? Does she need some extra time with mummy? Or a tutor? Or the teacher?

Go easy on yourself. Lots has changed, it's going to affect you all in different ways.