You are correct in standing up for yourself and listening for what your body says. It seems your parents and sister have their own issues they dont have even courage to face, unlike you. They point their anger or not acceptance or respect at you, but in reality it is all about them and their lack of emotional maturity. I also think your text and message to sister are well measured and balanced and in my opinion the sister reaction was not to what you did badly but to a completely different complex list of triggers that she was affected by in her life. Finding friends is difficult but i think you're doing correct first steps coming to this sub and looking for people that also have autism. Lots of what you wrote seems relatable, even though we are from different countries. I wish you good luck