why must this happen to me...

I gave up my childhood for my little sister. I took care of her. I protected her from my drunk father, and I protect her everyday from all the shit my parents do. Yet she treats me so badly, she is always saying the worst about me, which most of the time isn't true, and hitting me or kicking me. I HATE HER SO MUCH! I broke myself for her, I am ALWAYS protecting her but it's never enough...