The best short description I've found to determine which label most describes you is do you tend to "recharge" with a little quiet time or do you need a group of people to recharge.
By that definition I'm an introvert. I was shy as a kid but not as an adult. I grew up and matured as do most introverts. I'm confident and have no problem talking to others at a party or elsewhere. Once I've met and chatted with whomever I found interesting then I'm ready to go, otherwise it just feels tedious.
If I was feeling "burned out" my first thought wouldn't be "hey, let's get a group of people together, that would be relaxing"
I know a female who is very extroverted. She likes nothing more than to get a large group of people together but then once everyone is there (if it's an outdoor cookout, for example) then she will hangout with a small group of close friends but enjoy having the larger group all around her to look at. It makes her feel relaxed.
I'm definitely not the type that would go on vacation with a large group. Even with that female, when we hang out it's usually one on one although I've been to a few of her parties.
I'm not the socially awkward type of introvert but the rechanging thing does apply to me.
For the older US crowd, there was a famous TV talk show host (Johnny Carson). He was very outgoing on his TV show but in person he was very much an introvert. Being an introvert doesn't necessarily mean that you are shy, socially awkward or lack confidence. You could have those traits but you could also have them and be an extrovert. They aren't really related.
I think it is pretty binary for most people. Do you need a little alone time (can include being with wife/girlfriend/close friend) to relax do you need a large group to relax?
I'll get together with some people to go out in the mountains to go rock climbing. Usually two people with get together to do that and sometimes you'll invite someone and they'll go out of the way to start planning "hey who else could we invite so that we can get a larger group together"...why?