I need someone to talk to about some things

I'm 15 (16 in December) I have anger issues/ocd/anxiety and eating problems. That's here just so you understand the rest of the story and what bugs me.

School started two weeks ago and stressed is an understatement. I absolutely need my house to be clean and my whole family are just absolute pigs. I clean and organize every cabinet in the kitchen and thy know how I feel and I get back late at night and it's trashed. And when I say trashed I mean there are dishes pouring out of the sink- shit all over the stove- wrappers all over the floor and cups and stuff everywhere!! I calmly as I can to my sister (she's 27 lives at home with 2 kids and refuses to get a job even though she has every opportunity) ask her if she can fill the dishwasher so I can reclean the kitchen because I need it clean before I can go to bed. She gets in my face and yells at me and my mom yells at me and tells me to stop talking to my sister like a piece of shit. My sister has a room but it's up to the door knob in trash and she can't close her door so she lives in the livingroom and she trashed it. I long for my time home alone so I can just clean everything from top to bottom and she just comes and trashes it. She gets away with everything. I understand it's hard being a mom but I've never met a mom who just lets their baby throw up all over couches and not be bothered to clean it, she leaves diapers everywhere and I'm just constantly stepping on toys and food from her and my mom and they get offended when I say I don't want my boyfriend to come over. Just now she was filling the dishwasher purposely talking to my mom about how much of a piece of shit I am.

Now onto the eating- I was eating under 500 calories a day and I was passing out and just I could feel myself withering away. My mom always tells me that I'm so fat and no one will love me if I'm big like I am and that's my worst fear. I lost 90 lbs and went from XXL to L. She always threatens if I don't eat what she puts on my plate she'll take me back to the clinic yet she will be like "I'm just going to eat a sandwich today that'll make me loose weight" like what the fuck.. my mom is about 400 lbs and my entire life has been about taking care of her while she lays in bed and sleeps all day and eats full pies and liters of soda. Yet I didn't want to eat at all and she called me fat. I just can't do this anymore. If I ever do anything wrong she threatens to get to gun and kill herself. She touches my chest and my ass and I constantly tell her not to and she still grabs them. Whenever I bring up her not doing this she gives me the excuse that it's nothing cause she was actually raped.

I just need someone to talk to please.