I am sorry if I am off base here but are you very young? A minor? If not, then do you two live together? Do you have to? She doesn’t seem to think of you as a grown up. Maybe time to look to maybe live with roommates rather than mom?

Honestly your mom’s opinion on your relationships or friendships is kind of irrelevant. As an adult you can date or be friends with whoever. What she thinks is of no importance.

As about toilet, I’d just buy a new seat and look for a handy person to attach it if can’t myself and not worry who thinks who broke it. I’d say if it breaks that easily, it needs to be replaced anyways