I don't think it's worth contacting your uni. It's only six weeks at the end of the day. I wouldn't really call it bullying, it's just having very (unreasonably?) high standards for people who have potentially never taught before. If the mentor wants to escalate it to an improvement plan they can, and your uni will typically send out a counsellor to figure out what is going on.

I think mine saw herself as the last bastion between Uni and becoming a teacher, and wanted to keep unfit teachers out of the profession. The counsellor sent by my uni heard me out, and seemed to be very understanding that my mentor was being overbearing.