My sisteris always sayings things like "that doesnt look good on you" etc help!?

My sister is always saying that im ugly, and whatever shirt, hair length etc i like she ll go "nuh uh thats not for you" Or "i dont think that will look good" She always goes how it will be for her, or it will look nice on her. Ok she is like the slim tall one, and im the sort stocky one, but like c'mon i was happy with the decision i made, and she tellls me basically everything on me looks ugly. My hair its realy long right now, too long for me because i cant even put it in a decent ponytail without all the hair being pulled back , or pieces sticking out etc. And its too long, and i just dont like it. It was nice when it was reaching my..uhm lets say midway of shoulder/ . Now its just reacing the end of my , and my bangs are now touching my collarbone. Its too long, clothes are ugly on me or something. Even wh nail polish colour! She picks and picks at me. Im really stressed already due to friends, school, my parents, and now she makes it worse. I cant tell her to stop things fly ut of he mouth, and if i do she will jsut mock me and **** me off. I want a hair cut, and its hard for me to find clothes that look decent or nice. D: grr!!!!!!! idk wha to do. she made me in a crappy mood, and i just wanted my hair cut and she says sort hair is ugly on me.