Why can't I have nice things

My mom but mostly her boyfriend, they make these stupid remarks about me not doing enough housework. I hate it. It upsets me and I cry every time they do this. Yet if I bring up how I find that unfair as I do quite a lot around the house and for them, they act as if they'd never say such things. I hate it and I hate myself because of it.
My mom says she doesn't think these things but when they happen and I get told I'm not doing enough, she doesn't step in or say anything. So what am I supposed to think.