I've cancelled a session because I was worn out from prior long sessions, and I've delayed sessions because I was too upset or feeling overwhelmed from previous sessions.

I am so sorry you're struggling with the issue of possibly needing to change therapists.

Sometimes when an employee's not doing well, they're given a Performance Improvement Plan: do you think if you and your therapist could work out something concrete regarding your shared goals of getting you better, and you worked with that, it might change anything?