I've decided to just ask away from now on, since it helps to get answers and reassurance

OK. So, for my friends birthday at the end of April she is going to a festival, like the ones with tents and portaloos. Most people will already know where I'm going with this...
I don't want to go! And obviously I can just say that, but she asked a while ago and I said yes, but the emet has gotten worse since then. She's also one of those people who doesn't easily... Understand. And she has gotten annoyed at me a few times before because of my emet and Aspergers, even though I really can't help it... It totally stresses me out when she gets like that so I don't know what to do...
I'm totally petrified to go to the festival because of all the germs and alcohol and confined spaces and crowds and just the whole experience of it that I'm sure many of you understand.
PLEASE! Any advice is welcome and appreciated!

(Extra details: We are both 15, female, I have Aspergers - which I think has something to do with this, she is very confident and 'blunt', and often upsets me without realising.)
If you want to know anything else just say :P