I think that I hate my sister...?

I always try to be kind to her and help her when she's down but she is making it harder and harder. I am 16 and she is 23. She is constantly putting me down and making fun of me. She's cruel and backstabs all of her friends but acts nice to their faces. Her boyfriend worships her but she's always cuddling other guy "friends." She is stuck up and rude. I get sick monthly (if you know what I mean) with painful digestive issues. She says I'm faking and wakes me up early by yelling insults. When she has the slightest cold she makes me wait on her. I can't say no to her and I'm bad at arguing. Even when I do say no or fight back she doesn't care. She doesn't plan on moving out anytime soon and I don't know if I can't put up with her harping on my every choice. My family treats it like its no big deal and she always plays it down in front of my parents. What should I do?