Am I too self conscious? It makes me dislike people

I sometimes get disgusted, yes literally, when I hang out with other people. I don't know if this is the case for a lot of people, if it is an "autistic thing" (I do have autism) or whatever, idk. But the way some people so quickly become jealous of their friends for example, for hanging out with others, or just for them talking to someone about something said person doesn't understand because they weren't there when it happened, it makes me irritated.

Let me give an example to make it clearer, since it's hard to explain:

A few days ago, me, my friend (A) and my friend (B) went to friend A's grandparents summer house to just hang out/sleep over/ drink. I have known friend B since we were 6, and we are now 19. Friend A and I got to know each other after high school, idk what it's called really because we live in sweden and here it is called gymnasium, is it senior high school? Idk. We met at this new school at 15 years old I think and have known each other since then and we are now very close.

So, friend B is childhood friend, almost like a sibling, friend A is my other best friend that I have a LOT in common with. Like clothing style, music taste, humor, hobbies, etc.

You know how everyone says "duos always work, quartets always work, but trios just never work". I never really understood why it wouldn't work, because I never have a problem being in a trio. I enjoy talking to them all, or one of them, or they talk with eachother while I just chill in a corner. But for some reason, they don't think like that. Immediately one of them gets jealous. 

When it was me and friend A who talked about the things we have in common, or simply DO things that we both like and friend B is not really into, friend B comes to me and starts whining about her not feeling included and wanting me to see her, take care of her, talk to her, basically. It annoys the hell out of me, like, include yourself then? Why are you sitting there feeling sorry for yourself? Or go do something else in the meantime while we just do our thing for a VERY LITTLE while. 

And vice versa. Me and friend B are joking about our old school, the people we knew and very old inside jokes. Friend A comes to me the next day and says she is jealous because we are joking about things she doesn't understand. Literally what is the problem? There were times where the two of them sat in the living room and hung out, watched monster high, laughed and drank beer while I was lying in bed listening to music because I simply felt like not socializing. I had NO problem hearing them laugh together and me missing out on what they were doing.

So to sum it up, I feel like I subconsciously have the responsibility to always include everyone/make sure everyone feels included even though I'm probably not even supposed to think about it. I think people are childish for only thinking about themselves and fearing not being included every second. I would have as much reason as anyone being afraid to NOT be included, but I simply don't have the fear, because I let people be people. And this also makes me kind of dislike my friends sometimes, and wishing I could find "real" friends that doesn't get jealous the second they aren't included. 

Am I being mean? Am I overreacting? Or am I just introverted as hell please comment, I don't wanna feel alone in thinking about my best friends like this. 

-noie