((((((((my3sns))))))))))))

Not to go into details... but were you talking about abuse or something like that? I know that for a lot of people (myself included) that it can horribly trigger and you dissociate and basically some part of you comes out that... well, is and isn't YOU. Basically a "younger" you ... whatever part of you is holding onto the "bad stuff" that's happened in your past. I know it's scary, but I've never experienced it to that degree before. I'm sorry that it happened.

Perhaps you should tell T about how you felt afterwards, and then make sure you learn some grounding techniques so it's more easy to stay "present" in the moment? (Even though that is really hard)

It's hard to talk when memories and feelings (or even feeling like nothingness or that nothing seems real) get the better of us. Go easy on yourself! You did good - you got home in one piece. Perhaps in time you'll remember more about what happened in session, or you could ask T if you really wanted to know.