Are grievances anonymous and how do you file one?

RCA here.

Supervisor is becoming aggressively petty and arguably abusive towards his staffs personal lives. Example, I have learned not to tell him I like routes because I have told him I like two specific routes and haven't been on them since and I was on both of them regularly up until that point. And I am in school and have two days off this week. I scheduled finals for the two days off I had and then he changed the schedule last minute and gave me a clerk shift, which I didn't know he could do. When I told him that I had scheduled exams he told me that didn't work for him. So now I have to attempt to cram in exams in one day and go in tomorrow or lose my job.

Side note, I am quitting as soon as I can find a replacement job in my area but they are few and far between.

Edit: I did call out Saturday for having an almost 101 degree temp. Which he did not like.