Sorry to hear that you were triggered during your session, Claritytoo. It's happened to me, too, though I always seem to switch when I walk into the parking lot or when I get into my car. In the first few months of sessions, it would happen nearly every time as I left my T's office, twice a week, for weeks on end. If you're current T doesn't work out, will she be able to recommend you to someone with more experience helping people in your situation?

p.s. That's a great grounding technique, PurpleFlyingMonkeys. The 5,4,3,2,1 of it is very smart. One of the easiest ones that works for me more often than you might think is counting back from 100 by 5's. I usually only have to do it once and I feel better and it keeps me from sliding too far out of focus but if I'm having a rough time and I can't remember any other ones, I'll keep doing it until I feel better.