Stressing Over Hypothetical Situations

Hello, I have never posted on Reddit before. I don't have extreme OCD, but I definitely have a lot of issues with fixating on things, especially with work. I have had a very stressful week and, after getting out of the shower before bed, started arguing in my head with a difficult employee in a hypothetical scenario after JUST telling myself I would prioritize stress management over work. After a moment, I became frustrated at myself and punched myself in the chest a few times and headbutted the shower tile, telling myself "stop" repeatedly. I didn't hurt myself or anything, but I regularly fixate on work and difficult people I have to work with and/or manage and keep finding myself in situations where I am angry that I can't stop, even when I want to.

For reference, I do have a therapist, and managing work stress is usually the biggest subject. I have been listening to a lot of Reddit story podcasts and felt some relief when I realized I could post something myself. Does anyone here fixate on difficult people on a daily basis? If so, what are some healthy coping mechanisms you use? I have some, but (of course) I have a much harder time coping when I'm tired and overwhelmed. Physical aggression isn't a common occurrence for me, but I will often find myself so frustrated that I can't stop thinking about something that is stressing me out and distracting me from functioning. I am an artist and musician and would much rather focus on things outside of work that feel meaningful.