The Terrors of Tasmania

Ehm, I just discovered today that in two weeks, I'm going on a school camp thing to Tasmania.
Which worries me for two reasons.
one: I don't really know people at school very well because of lack of attendance, so there's the whole paranoia of being by myself without a computer and whatnot, not being able to talk to anyone for two weeks or however long the camp thing is...
and two: I have crappy clothes with holes and stains and whatnot, and the ones that aren't like that all make me look horribly overweight. I don't like looking fat. I'm vain. Shut up.

So yeah, basically I need to drag my arse to school and try and squeeze some money out of mum for clothes or something, because I sure as hell can't afford them. >.<

Anyway,
I'm up until 1am, because of incredible back pain, and taking pills, any kind seems to make me throw up for some reason, so they really can't help me, and I've got a heat pack thing on, but it's still just really unbearable. =/ Any other ideas of how to solve it?

So, being up until 1am, is gonna screw up my sleeping habits, making it harder for me to get to school on time, and because I hate showing up late, it's gonna be harder to get there at all, which is gonna make mum unhappy, which means she's not exactly going to throw money at me to spend on clothing, so I have to go on the school thingo looking like crap, and because I'll be missing school, I won't know anyone, which will make the time there unjoyable. God that was a long sentence. I think into things too much.

Also, why does mum have to always be so snappy and mean towards me? I know I'm a useless shit that rarely does anything around the house, I probably could do it, but I just don't have any motivation or whatever, plus it's all housework I'm supposed to be doing, which will just do wonders for my back.
Argh.
And I can't show her that I'm all upset, because then she'll get all upset, call some psychiatrist thing, stick me on medication, which will make matters worse. So, yeah. Just have to wait 'til I get over it.
Plus, she just DOESN'T LISTEN.
one example
Me: I've lost my jumper
Her: I'll look for it
Me: I've already looked
Her: It must be at a friends, better call them
Me: Already looked at all friends houses aswell
Her: It has to be somewhere
Me: It's lost
Her: Not it's not
Me: It's lost, it's gone, never gonna see it again
Her: I'm sure I can find it
Me: you'll never find it, it's been lost for months
Her: you just have to look harder, I can find it
Me: No you can't
Her: yes I can, it's probably lying around in the house

And it goes on like that, for ages, She refuses to believe whatever I say, forgets the fact that I said I'd already checked the house, that it's been missing for months or whatever, she's still confident she can find it, even now weeks after that conversation.
Ahem, it just drives me crazy. :(

P.S.
Rattus has about a week to live