The only common thread between the two major salvia trips I've had was loss of control and loss of sense of time. Each time, it was like I could see ahead and see what my next move would be (the first time was especially bad, because every "move" I would make would get replayed, so the only way to add a "move" was to go through every previous move over again), but I had no control over it (as if it was already decided, and I was just a puppet going along for the ride, basically.) It might sound silly, but it was terrifying.