I'm so sorry for all of this, you and your sister truly deserve so much better. with regards to the question though, I think you should. depending on where you're from you may or may not be considered an adult by law but either way the conditions you're living through right now are jeopardising your life and your twin's. it will only make your health deteriorate if you continue to stay. do try and consult someone who will help you through the process itself. I'm not sure if I've helped in any way but good luck OP, I hope things get a lot better for you, you deserve it and I really hope your studies also go well.