aproudbyg- i am boiling inside that your class would make fun of your bro being otd, or about your oarents. What chutzpah, how not understanding, how painful. The fact that you nonetheless view yourself as a proud by girl is amazing. You have inner strength that will get you through pain and bring you far. Do you have any friends from school or the neighborhood you could go to for shabbos, meals or afternoon? Are any of your brothers married and living near you? I’d even suggest finding a family who takes guests for shabbos from shabbat.com if you can. Find yourself a mentor please. A teacher or neighbor you respect, a rav or rebbetzineyou can ask your questions to and ask for advice from (they may also have guests for shabbos meals and be glad to have you join them), a psychologist. Someone you can discuss this with who can practically help or advise.
It sounds like you already do, but know you are not at all responsible for your brother’s or parents’ actions. They have their challenges and tests, you have yours, and their actions don’t affect who you are, and you NEVER ever deserve to have someone rub those in your face. Besides the fact that noone of your friends has the right to even begin judging them.
You really sound strong and it impresses me. And i’m glad your sense of humor is still intact :). It’s one of the best tools for getting through tough situations