I feel egnored? and depressed..?

i feel egnored and left out of my family my parents care bout my sis so much and they forget bout me and they neva listen i cant tell mum cuz i tried to but it didnt work and im homeschooled so im wif her 24/7 and i get so depressed and sad and ive startin cuttin. i dont no wat to do.i wanna run away but theyll find me.. i cant tell anyone either. and i cant talk to a doctor cuz then my parents wuld find out.. i need sum help...