I think I understand what you're saying; I use to feel like someone had suddenly grabbed me by the back of my shirt (blouse?) and yanked me back 45-50 years sometimes. It was very disorienting and scary. I was always afraid I wouldn't be able to "come back" to the present but I always did. Sometimes grounding would help, if I could get "interested" in something in the here-and-now, see the "normality" of the present day. I use to go out and watch the cars pass in the street or, literally, touch a tree, wander down to the nearest convenience store and buy something small/inane, etc. Once when someone, not my T, called to tell me my T wouldn't be back for the next session like she'd thought she was, just rubbing my hands over the material of the couch and "registering" its color and presence saved me there.