Am i out of the line, or are they? ?

I recently just moved in with my brother and his girlfriend, bcuz my boyfriend was mistreating me. Anyway I have lived with them before, they are charging me rent $300/mo. Including $25 a week for food. Which is fine, but my brothers girlfriend is always ***** at me about stupid stuff allllll the time it is very annoying! Like for example one night she had asked me when I got home from work to wash off my plate and put it in the dishwasher and start it, I said ok. Well, I got home and she was sitting on the couch I said hi and she just ignored me, I finished eating and went to put my dish in the washer but there was no room so I figure I would just wash it myself put it away and start it no biggie. Well she asked my what I was doing I explained and she got all pissy and started shoving dishes around in the washes just to fit this dish I had already washed. Then my brother calls me the next day while I'm at work and told me I was being too loud last night. I told him it was your girlfriend, and he said she said it was you! Other things she does is one day I forgot to put away the cereal box after I was done with it bcuz I was running late to work and I have to take the bus. She sends me a picture of it and asks me what's wrong with this picture, I'm like seriously just put it away. She get made when I'm in the kitchen bcuz I "leave crumbs" I always wipe up after myself but whatever so I just basically stay in my room unless I have to get ready for work, I've lost ten pound bcuz I don't like to eat around them bcuz I'm afraid she'll ***** about something. So tonight I went out to the kitchen (she's sleeping) I went to open the fridge and she had cut out an article on house rules when you take family members in about helping to clean taking out the trash keep your space tidy and so on. It really pissed me off bcuz one I pay rent I should be able to at least just take care of me and my stuff not the whole house 2 bcuz she just did that to be a ****** and 3 if they want to charge me rent then they should treat me like a renter and stay out of my room I leave them alone they should leave me alone my brother is always saying how I need to make my bed, I'm like I'm paying rent stay out of my room.