Thanks for your suggestions. She has traveled before and not been so fussy, but maybe she's aging like I am.
At home, she uses prewounds fine and I changed from a regular wind it myself bobbin to the prewound and she worked fine at the class.
I have thought about it and realized DH loaded her in her wheeled carrier on her back in the back seat. Horrors...maybe she got car sick?
Anyway, next time I'm going to unthread her and thread her fresh after we get to class, including a fresh bobbin. I am also going to try lowering the needle that sure can't hurt. I'll mention you are are concerned about her, maybe the attention will help.