Shaken after working with a NPD client and difficulty with regulating

I’m feeling really disregulated after seeing a client I’ve diagnosed with NPD and some of the cold, unempathetic things they’ve said today. I couldn’t get them to see how cruel and uncaring some of the statements were (in addition to their self centered actions) and that’s when I decided I couldn’t do it. I’ve referred them out and let them know that I couldn’t work with them due to my lack of specialty in this population. I felt viscerally in my body that I could not continue with them but I’m still distressed. I feel like a bad therapist but I don’t think I could be a good therapist for them. If you work with NPD, I really commend you and your work is so valuable.

I’m having a harder and harder time resetting now that I’ve brought my caseload up (20 sessions a week) and had a full 20 minute panic attack after a 7 session day last week in which I couldn’t stop cycling through panic about my clients, specially past clients. I think I’m getting close to burnout. How do you all regulate between sessions? Especially after sessions that activate your nervous system like this did for me.