We're not supposed to diagnose on the forums on PC. I'd like to point out that you used the term "slime" to describe yourself (which, considering the way you used the term could be interpreted as a negative self-image) and then made several assumptions about "the whole world," "nobody," "everyone," "every last person" that I doubt are actually true.

People learn how to behave, if by behave you mean adhere to a set of behaviors generally considered appropriate for the society you're in. You don't say how old you are (and you don't have to); however, I can offer an observation that young people often bumble about for a while before they feel as though they have found their place; and this feeling of unsettledness can come back at mid-life and at old age, I don't doubt.

The coming of the internet and hand held devices (tablets, cell phones, etc) has seriously disrupted the sort of socialization that people who had to deal face to face got by the boatload by virtue of actually being face to face with other people. So there is that, too. This can sometimes become more apparent when circumstances change: going away to college, starting a job where there is face to face interaction, moving to a new neighborhood, etc (pre-COVID 19 for most of this).

You can probably help yourself by choosing one word or phrase: 'alienation,' 'feeling disconnected' or 'existential crisis,' as examples, and then searching it in a search engine, to see what pops up. Then you can read or watch videos to delve more deeply into the areas that resonate with you.