I'm sorry you're going through this. Most people crave validation from their family so you're not being irrational with your sibling and parents. Chat with your parents to get an idea on their point of view then share yours. Hopefully that will give them a better understanding on how it's affecting you. I know, I know, parents should know but I hate to break it to you. We're all silly humans, some just mask it better. And, perhaps you can try to have a heart to heart with your sister when she's in a good emotional space. Try to figure out what's frustrating her. Maybe you have a solution to her issue or at the very least, she'll see you as a friend and not as adversary. If that doesn't work, pray that her coat zipper gets stuck or she spills red color juice on a light shirt :) All kidding aside, most carry a little pain and unfortunately we can hurt the ones we love intentionally and unintentionally. If the heart to heart talks doesn't work, standing your ground will have to look different. Basically, you can’t force your family to hear you out or meet your needs in this moment. I know that sucks. They'll come around when they notice you share your thoughts one time and no longer engage in the back and forth with your sister. You'll have to make more time for the things you enjoy. The hobbies/activities that brings you joy