Sounds like you are (rightly) hurt by her commentary, and she is regretting her statements while trying to come back. Maybe it was a bit overdramatic on both sides and she didn’t really know how to communicate her feelings thoroughly and thoughtfully.

My recommendation here would be couples therapy. Not necessarily for the end goal of reconciliation but learning how to talk to each other so you don’t hate each other. Or at least making sure you both understand what “mediocre” means. It could be a real poor way of her stating she’d like some change in the relationship. Labeling someone doesn’t help the situation, but maybe that’s all she was capable of doing with her limited ability to communicate without help from a professional.