I Think I Want To Run Away?

I really hate living in this house. Me and my mom always get into huge arguments over my dog throwing up everywhere and keeps telling me to get rid of her even though ive had her for 8 years and i cant take her to the vet cuz i dont have money or a car and my mom sure doesnt care enough about her to take her and my 13 year old sister drives me crazy. She acts like a 5 year old brat and cusses at me all the time and I never do or say anything back even though I want to kill her. She makes me want to kill myself since I can't do anything to her and she drives me insane. And my mom let's her act like that to me and call me all the names she can think of. My dad lives in a different state and even if I tell him what's going on he won't care or do anything. I hate living with these people I want to run away but I know that's not a very logical solution for a 15 year old girl. And I don't have any relatives or friends that would take me in and i tried telling my best friend about this but shes an only child so she doesnt understand. shes acting like my mom and saying i CANT LAY HANDS ON HER because shes younger but shes only 2 1/2 years younger than me and shes taller than me and bigger than me. So I really don't know what to do. I REALLY can't handle this any more. I really just wish I could die or something. Advice would be helpful... And I'm sorry if I'm acting like an immature little brat I know..