I...feel something of the sort. I don't know if I would call it lost-ness; it's more of like a lack of sense of self for me. I know what I feel, what I want, how I see the world....and yet I don't. For everything I come to understand in myself, I lose that understanding, then regain it, but every single time it seems to be somewhat detached, somewhat surreal; less tangible than what others say they think or feel, in a way.
I think some of my S friends help draw me out of myself so I don't notice it as often. But when I'm in myself (that's the only way I know how to describe it; there's a distinct difference from when I'm viewing the outside world, when I'm caught inside my own mind, and when I'm in my mind but registering the outside world, kind of in the way of looking through glass like oceanic99 said) it's as if nothing's quite as solid as it should be. It's fine when I'm only lost in myself for brief periods, but if I am in myself for extended periods or too frequently, I begin to lose what I have navigated and what I have not, or what I am aware of, am fleetingly aware of, or was never aware of at all.
It's the strangest thing, that; there are times when the "real" world seems something less than real. There were times when I'd have to really think to grasp what goes on in the "real" world because the place in my head seems so much more solid, but less tangible and more dynamic, if that makes sense. There are times when I notice that I don't really remember the real world, or it's very dim, even if it was recent; I know it's not my memory specifically, but rather there was nothing for my mind to register, since I never really noticed anything in the first place.
How do you really describe it? I've become used to it myself, but once I start to think about what it is again, I'm mystified. I understand myself better than most; I am more confused about myself than most. But how do you explain that to someone who doesn't know? I've tried to get friends to read about INFJs to kind of have a glimpse at this dilemma, but I don't think they really get it; I don't think I seem that complicated on the outside.
I don't know. Lost-ness is probably the only way to really describe it.