Im a teenage girl, going through some REALLY rough times? Please read... I need some advice.?

1st of all...having a disease isn't your fault and you shouldn't feel bad about it. You cant really do anything about your mom's relationship or any of her other actions. Parents always think they're right (that's just how they are). Arguing with your mom won't help anything. If you want your brother to start behaving maturely then you might want to calmly explain to him that he is causing stress on you and your mom (if he's young-like 10 or under-then he probably won't understand). I'm a 18 year old guy and I've put up with a lot from my family so I know what its like. Don't get too discouraged.You need to find a hobby or something that like to keep your mind at least partially off of your current situation. One day you'll be free from all that stress. You'll have a job,a car,your own money,your own house,and your own family. You just have to wait until then.