Mine used to come to work every day with me, and after the "incident" I couldn't rouse him to get in the truck and go.
He just stayed home and slept. I would come home for lunch, and he wouldn't stir. THAT was unusual. After about three days, he became himself again. He was an old dog at that point, that much exertion was likely too much.
I try to watch them closer, now. I don't want to kill 'em.

Best,
Ted