I felt as if I read something I wrote. I'm in my 2nd year of college and during exams I was feeling really overwhelmed + I was just going through some rough patches mentally so I just emailed T maybe 2-3 days before and said that I did not want to come in because I was having a rough week and I didn't think it would benefit either one of us if I did come in. My T asked what happened but also let me reschedule to the following week. I think it's perfectly fine to cancel the session if you arent motivated to talk about what needs to be discussed because then it'll be a waste of time and money.
I think I've cancelled maybe once because of that and tried a few other times but my T insisted I go in and talk about what was going on, and 3 because I was genuinely feeling unwell !