Hi @Cats101
Was the constant tension you mentioned just between you and everyone else, or between everyone? I don't think you did the wrong thing. If your other friends want to accept this rude behaviour from that one person, then that is up to them. Maybe they didn't mind it because it sounds like none of it was directed at them after you spoke up. It's really hard, not to mention takes so much courage and strength to set boundaries with what you will accept from others and what you wont.
I tend to see things these days are that we can't control what people say and/or do, but we can control how we react to it. And you decided that behaviour was unacceptable and spoke up about it. All your friends could learn a lot from you.
I've had friends where we teased each other, but we had been friends for a long time and we knew each other well enough that we knew it wasn't a problem. If it was someone new or anyone said "Hey, i really don't appreciate that." we would have respected that and stopped doing it. It just seems like there isn't that respect here for you. If anyone did something wrong it was your friends, and not you. They're certainly not showing you any respect. If anyone should be sitting down wondering what they did wrong, it's them!
I know this probably doesn't help you much at the moment with all this tension. Maybe if you explain it to them they will understand, but maybe they're just not mature enough. Either way, you cant control how they react, keep that confidence in yourself and your strength to know your own boundaries.
I hope you can sort out this tension soon, it can't be a great environment to live in. I wish you all the best with it, but we're all here for you if you need that support dealing with it.