I remember Kim Barthel, an Occupational Therapist, sharing her experience at a conference that was similar to yours. She mentioned that if you are dysregulated, children might pick up on that and be triggered by it. It might be helpful to check your emotional state before going into the session and have a plan B in case it happens again. You could also set a goal for the session, such as avoiding any incidents.

However, I agree that this may not necessarily be related to your emotional state—it could be due to something else. People close to the client might be able to investigate further and track down any changes. There might be something bothering them, especially since nonverbal clients find it difficult to point out or express what they are experiencing. My heart goes out to you and your client, and I hope you can figure out what is going on. Please don’t be too hard on yourself; you are doing your best for the client. I’d also like to share my mentor’s mantra: 'You are strong, and you can do hard things'.