Memories usually have its origins, then they accompany us for a while, dissolving, coming into oblivion and becoming a background for new brighter events.
Sometimes I recall memory, or thought, or feeling, or even some sort of realization of something which came from the very profundity of mine. Namely the sense of self, let’s call it “essence” or “selfity”.
Don’t mix with egoism. Probably there’s something similar to egocentrism, and yet it’s ultimately imperfect and flat synonym.
This sence usually comes to ” grown ups” in times of disasters, depressions or it strucks us at some turning points of our live.
But those who was close to Death, who was in Death’s hug will get it   way faster.
The sense of “self” in moment of Death is incredibly sharp. The whole life goes through you mind, and it hits you, that everything, just everything you see and feel: friends, children, parents, husband, ground, light, the sky, everything just came and will be gone. And the question appears “What is going to be happen with Me?”

Things and thoughts fly fast through you. Usually we think by virtue of words or some language. But at this point Language is superfluous.
Any sort of feelings disappears, even the pain retires and become a merely background. You’re about to die. Now. And only “you” exist. And sometimes this question “What is going to be happen next?”
And this sensation of “self”.
I truly believe, everybody can recall it, and thus recover it from the ocean of oblivion.
Subjectively saying it’s like you are the only creature in whole universe, the rest are just “objects”. And you are dramatically alone and there is only void around, the ocean of nothing, of dark dark emptiness.
And everything you see is merely sophisticated cinematograph. But you are alone. And it comes to you as an ultimate knowledge. You realize, that you exist, you existed and you will exist.
It is subjective once again. May be there is indeed only one creature in whole world, but it’s quite happen to be, that this creature fills up all the bodies in universe simultaneously.
Below are my observations.
So I’ve catched this sensation and tried to track up its origins. When i was a kid I felt it much more often and there was no need in shock. I usually was in just a good state.
And when I followed this thread even deeper, I found that it is just my very first sensation!
It arised even before I started distinguish objects by my eyes and ears.
Everything was just a white noise by the time this feeling already was quite clean. As time goes by I started to fill up objects with meanings, started to connect what i feel with what i hear and so on. And this feeling of “self” started to disappear.
Though each time I come back to this “self”  I feel weird. It’s sort of fear and calmness at the same time, it’s feeling of lightness and yet I can not move.
The live at such moments becomes a background turning into noise. And only one thing is in the air: the reason? Why I’m here? And for what? What to do here? It’s hard to put it into the words form, since this question has been emerged long before any of words.
And i think this is exactly the question which makes us curious in very first days, forces us to perceive this world in our childhood.
It is the implicit source of all our thoughts, and also the reason of what makes us working on just an ordinary daily solutions.
And even if you’ve forgotten your “self” and its questions it doesn’t mean that “self” and its questions disappears. I’m about to think that all our activity is caused exactly by this feeling and “question”.
And just like some details distract us from main activity, we are also distracted from the questions which outcome from our “self”, thus we are going deep into the forest of needless and dummy things.
Buddhists say, there is no “self”. Well they are probably right their own way. Since I didn’t find “self” in its regular meaning, which means “Identity” or “personality”. Latter is something non-resident, which comes to us and.. leaves us. But even Buddhism is introduced for.. Somebody? May be some part of this “somebody”  exists?
I’ve looked into myself and found this feeling, and called it “self”. And I’m sure it lives in each of us. Just don’t be afraid and think and recall it. Recall yourself.