My Prayer

my Lord Jesus, today was one of my hardest time. there's a question in my head, what exactly do You want me to do? 
Today my father came to the town where I live. when he dropped by my boarding house with my sister, to deliver food from my mom, dad asked, "if you have not made up with sist?". I can only shut up and stared at my father's face, he was sad, Father. his face grew morose when I say that I'm tired of succumbing to her. 
I really don't know what to do.on the one hand I want to forgive her, on the other hand I was afraid she would repeat the incident again. I'm afraid. not that I don't believe in Your power that can change a person, God. I want to make peace with her, because I don't want my parents so upset because of this incident, but my heart continued to scream and refuse to make peace with her. My biggest fear is if I can't hold my emotions and make this incident happen again and I won't forgive her, even my self. I'm angry, I'm upset at myself because I can never resist my desire to fight her back.
I never meant to hurt them.. I just can't forgive what she have done.. I always end up crying on my sleep when I was thinking about it. I hate my self because I can't handle it, I can't handle her behavior, or even fight her back. something always hold me and say, "it's not you but don't fight back. be patient". is it my fault? she's always right in their eyes, I'm the bad one, it's ok, as long as she doesn't hurt them. 
dad ever said, "you are younger, you have to succumb to your sister". succumb? how can I succumb to someone who always make my parents sad because of her sharp tongue?  
God, what should I do?? i can't understand this... please lead my way.. to You.