To be honest, I'm entirely unclear what all these terms mean.
I do know that I've known many people who were overwhelmed with stress and difficulties, and almost all of those difficulties seemed to be caused by other people in their lives (friends, family, neighbours, work colleagues).
Seems as if the main reason one needs social connections and people in your life is in order to have support available to help you cope with the huge problems caused by the other people in your life. Sometimes seems to me to be almost a zero-sum game.
Basically:
1. Being antisocial means not wanting to spend time with people & not wanting to be friendly with people. This is not the same as being introverted!
2. Having anxiety means you
want to do something, but the idea of doing it & actually doing it both don't make you feel very good. For example, I live with hardcoded public performance anxiety, where I have a myriad of effects that happen whenever I have to present in front of a group of people, whether it's 10 people or 500 people. I still do it as part of my job, but it gives me stomach pain, acid reflux, a headache, nausea, etc. automatically. I simply have an overly-sensitive central nervous system that I have to live with!
3. Being an introvert doesn't mean that you don't like people; it just means that the energy required to be around people, especially crowds of people (parties, classes, jobs) is especially draining, so then you need some alone time to recharge.
4. Being an extrovert means that your battery of energy gets charged up around other people, so being by yourself is more draining, as opposed to energizing.
Not everyone falls into these categories. Some people are just "normal" & don't mind hanging out with people either way & don't get drained or energized from social situations or from being by themselves. But it helps to know which category you fit into because then you can tailor your life around what gives you life! I'm very much introverted...I like people, I just can't handle being around them for a very long time because I get physically, emotionally, and mentally drained. It's just an effect that happens that's simply built-in, not by choice!
It's difficult because for many of us who are introverted, we'd like to spend more time with people, but our energy gets zapped doing so & then we don't feel very good, and if we push it, then we end up having a terrible time & needing a few days to recover. Whereas I've got extroverted friends who will go party at Burning Man for over a week & come home full of life, rather than drained to death, haha!