I felt really sick driving to a T session last weekend but was OK. There was another one about a month ago where I had to take a cab there (long story) and felt kinda carsick, so I asked to use the bathroom at one point. I thought I'd have to use the main building one that was kinda far from T's office, but he said I could use the one for staff right across from his office. I was like, "Wait, there's a bathroom right there?" He said yes, that normally it's only for other T's there, but he owns the office space (he rents it out to other T's), so he can decide who uses it. I ended up being OK, but I've felt better in future sessions knowing the bathroom is right there if needed.

Edited to add: I've also had panic attacks in session with current T, ex-T, and marriage counselor where I felt really shaky and light-headed, heart racing, etc.