More depression..

I know parents can be annoying, irritating, and etc. but they will always be your parents and they will always love you no matter how much you messed up. I hate the fact that my little sister find it "inconvenient" to take my dad to the store to and take him home then head to the mall. I don't care how long it takes or how gay it is, it's your dad. My dad has stage 4 lung cancer and we don't know how long he has left to live so why treat him that way? Why take him for granted because when we we're younger he'd always have to take us to school in the morning then back home and head to work. Sometimes he'd have to close his shop to pick us up from school then drop us home and head back to work. Why didn't we complain then? It hurts me so much to even think about it. Tomorrow is his birthday why can't everyone give him a break? Why can't people give ME a break? I'm so depressed with all this crap thats going on in my life. What hurts more is my mom is always one-sided. She always back my sister up no matter what. My sister is home all the time and she doesn't do shit. Leave the overly filled trash can there when she sees it, leave the dishes in the sink even when it's full, never vacuum the house. I'm sick of this bullshit. I'm sick of my parents not saying anything to her but when I come home it's all my fault. I'm always to blame. Why should I even stay here if it wasn't for my dad? Life is so unfair. My dad doesn't deserve to live the rest of his life like this. My mom will never understand me. She always think she does but she doesn't at all. In fact, I hate talking to her nowadays. She always think she's right about everything when she's not. She always try to make it sound like I'm disrespectful or something. When I go to school or do my homework/studying until late she always act like I'm going out to play or something. Nobody even knows how I feel. Nobody even cares.
        I'm going to spend the night over at my sister's tonight. Why sleep at home to this empty shell we call a house. First it's love issue and now family problems. I'm fed up. I'm tired.