This is a subject on which I truly obsess. You are not alone, everyday I agonize over how I am perceived by other people. I consider how I speak, look, act...everything. I know this sounds more narcissistic than anything, but it is more a curiosity that frequently turns to anxiety.
I begin to question the relevance of things I cannot control. Like you say
7,7 billion ways of seeing and experiencing the world
include 7.7 billion ways of perceiving a version 'me'.
I can often 'over-read' into what people say or what I think they're thinking.
I have however recently taken up a meditation practice, and turning it into a 'thought game';
I challenge my imagination to either visualize how somebody I can physically see is experiencing life and thoughts,
how a person (real or fictitious) does/did the same,
and finally sometimes I pick a memory as it passes through my natural train of thought, focus on every individual detail I can remember and create a 'vision' of it in my minds eye that I can enter in a kind of 'POV' capacity.
It reminds me that, if nothing else, I have created a small reality as I go. Memory and imagination serve to this purpose.
I read a fantastic quote recently that really struck me;
The universe is an open end sandbox RPG. There's no end goal. You can only get achievements. Some of them include making people happy
I am starting to believe there is no point to life, the universe, reality or existence outside of the sheer randomness and 'accidental-ness' of it all.
And whilst this sounds hopeless and depressing, I recognize and reflect on the idea that we can give our own lives meaning, and other people can give our lives meaning too.
Sure when we die it will be over, and, in the grand scheme of things, meaningless. But it was a fun play in the sandbox.