In an world where our civilization evolved so fast and so linearly, and where we get so little autonomy, it is more "normal" to be feeling that way than you could imagine. This mass society considers "wellness" only what helps it propagate itself, and that is just possible through the indocrination and domestication of little kids since a early age. We feel repressed, lonely, and hopeless, all that because our lives are being controled by some remote social structure that only see us as numbers. Some of the older people can't understand it because they helped to build this sick system, they wasn't the ones being treated as zoo animals by it all their lives. Hominids aren't used to see this poorly maladapted, vertical civilization as their "default" mode of existence, this is all abrupt to us on a biological and psychological level. They try to remedy this with antidepressants and by setting artificial goals for us through propaganda, but they don't care if we kill ourselves or if we grow up to be just barely functional.