A: Welcome to the problems of your generation. Though you may feel lost and alone you are in very good company with so many in your age group. The good thing is that some of your problems are just due to your stage of life – so, you will outgrow them. The bad thing is that some of your problems are due to the world you grew up in and unless you do something about it, things will only get worse.
It is normal to be questioning and feeling lost at the age of 20. You are transitioning from the rules of your parental household and high school to the relative freedom of living on your own and making your own decisions. This is metaphorically the moment when you have been pushed out of the nest and it's up to you to fly. That's a lot of pressure!
Some will do this with relative ease. If they fall, they make their way back up again. And some, like you, are so focused on themselves that they analyze every wing flap and critique every fall. All the while, they compare themselves unfavorably to the other birds. Eventually, most learn to fly (which for you means finding a career path and a relationship). It may take you a little longer than everyone else, but keep your eye on the prize and you will get there.