You did not make a mistake. Keep reminding yourself of that.
It sounds like you selected a school that is heavily focused on production--so presumably, you imagined a career doing shows after the degree. And fabulously, you have already made the switch into the professional sphere, without suffering the bad fit at your former school.
This is an important part of freelance life, which can only be learned in the field: there will be periods where you do not work. You will wonder, every time, if the last show was your LAST show. Until and unless you make the decision to leave the field, however, there will be a next show. Maybe next week... or next year. Finding meaningful (or even just sustainable and sustaining) sideline work should be somewhere in your top 10 priorities, since you have downtime. But under no circumstances should you allow a toxic school environment any more headspace, now that you've made the plunge into the work you wanted to do anyway!
If you feel that completing a university degree is important, do it. But please, do not return to a place where personal and professional boundaries are so blurry. If a professor had given me exercise advice, I would have been livid.