*Hugs* Aww sweety I sort of know where your coming from. I have a similar situation kind of.
It seems as if your parents don't know how to deal with the problems your having. It's like they want to be there for you maybe a bit too much and I guess baby you in a sense. Yet at the same time they'll want you to be like a full grown adult and be completely responsible and everything. It's like they can't pick one thing and completely stick to it.
As for your mother, I think she's worrying wayyy too much about you. It's sort of as if she can't seem to let her child go because she's fearful of what can happen if she does. My mother when I was younger did practically everything for me too. I'm still learning the domestic basics like cleaning, cooking (beyond rice, eggs, and easy stuff), etc. She'll do stuff like tell me to zip up my jacket or coat when I go out and for me to look out for traffic. Yes it does annoy the hell out of me but I guess she does it out of care. No offense but I know your mom is doing it for the same reason because she cares about you but it is starting to get a bit obsessive. This maybe too much to ask but does she have panic disorder? It sounds like she's constantly worrying way too much.
And with the siblings, my little brother treats me like complete shit. I get called fat, a whore, worthless, stupid, and someone who is never going to get anywhere in life on a daily basis from him. It's never ending. Yes it sucks and it hurts inside. But maybe he is just saying all of this because he's insecure? The boy doesn't have that much of great confidence. Maybe it's the same with your sister. She's probably really stressed out from this situation with your parents that she's just lashing out at you. Kind of finding a scapegoat.
Is there any possible way for you to possibly move out even for a little bit from your parent's home? From everything you've said it sounds like a really stressful chaotic and negative enviroment. Maybe moving out will show them that your able to take care of yourself on your own with the help of a therapist and be fine.