Pro tip: crippling social anxiety is not the same thing as introversion. If your social anxiety is cauing you that much of a problem, seek therapy or a support group. If you confront your problem, things can get easier. Sometimes you just need some people to talk to.

If you simply prefer to spend more of your time alone or in small groups, and you don't feel much anxiety in social interections, you probably are just an introvert.

The cashier at the drive through: "Can you speak up please?"
Me, who just said my whole order: