A sisters life

So I'm not really supposed to talk about my family on this blog, not because they or anybody I know reads it, but because I feel like if I say something "wrong" it'll come back to bite me in the ass. But since this topic is related to me (emotions). What I mean is, if she (my sister) is unhappy, it "rubs" off on me.

So what's going on with her is she's unhappy. She's annoyed by the fact that she isn't going anywhere right now. She's between jobs and gets financial support from the government. But in return (for the support) she has to go to these "classes" everyday. She hates them. The people who work there, the "students" and the whole concept.

What bugs me about her right now is that she's taking it out on us (mother and I). She gets mad about the littlest things and spends most of her time in her room. She isn't social, which is one of those things you would normally categorize her as. She's: nice, friendly, social, has leadership qualities.... and so on. But now, as said, she spends her time in her room.

How this affects me most is the constant negative things being said around me. People at school complain about other students and now at the house, she complains about mother and mother complains about her... I'm not sure how much more of this I can live with. I feel like I'm going to explode on somebody... then I'll have to say sorry and people wouldn't act the same around me again. So that is not an option. But I also hate confronting people. It's not something I do very often, because I don't ever get to the point where I'd have to say sorry or confront people. I'm nice like that ^^

So what do I do? Do I suck it up and confront them or do I wait it out? If I suck it up, do I talk to her or to both of them at the same time? Do I also confront my issues on confrontation?

Weight?

My weight has always been an issue for me. Like so many other people out there, I'm unhappy about the way I look and weigh. I'm not always unhappy about it. Sometimes I love the way I look. Sometimes I think I look hot, sexy, interesting, different, cool, neat, nice, beautiful, calm, clean... and so on. But every once in a while I do something or hear something and think, wow I'm gross.
Now... I know I'm not thin, never really have been, but I've also not considered myself fat. I'm overweight, but not fat... It's weird. My BMI tells me I'm overweight (actually it says I'm fucking fat...).
I follow other peoples blogs. Some of the ones I follow are about people losing weight. And some of those people are pro-ana. I'm clearly not, with my rolls of fat... but some of them are. I've wondered what I would look like if I was thin. Not a happy thought process (because you always end up back to the present and I'm not thin...). I'm going to stop my constant complaining now...
I live at home and have never made supper for only me. I always make it for me and someone (my sister or mother). So what I make isn't always healthy. I don't want to start buying healthy stuff because then they will comment on it. I very much dislike it when they comment on something I change. Especially when I'm self conscious of it. What should I do?