I can't decide what to do about her...?

[kate]

3rd paragraph has good information. The fact that she was mad at you for bothering her while she was upset makes it seem like the was dealing with a completely different problem that she might not be talking about? Do you know if she's having difficulties with(ex: family?)
The fact that she would freak that you woke her up from her nap is just ridiculous. That is not your fault at all!! Especially if you commented on Facebook. What is she doing going on Facebook while she's asleep? And if her phone gets notifications for that stuff, it certainly is not your problem.
The bickering about who is better is ok once in a while, people do it, but if you're constantly 1-uping each other than it doesn't make for a healthy relationship.
The joke thing is immature and you said SHE decided to play a joke on you but that it was the other kids idea. The fact that she went along with it sounds like she likes to see you squirm. She's being dumb for not talking to you after, although if you lashed out over something so trivial, like someone hiding your stuff, that's something you should reevaluate about yourself. It sounds like she messes with you BECAUSE you tolerate it, once you stop, she might find someone else to pick on.
She sounds kind've mean and a little manipulative, causing trouble and such. Dropping her might be best. You deserve to be treated with respect and if she's not willing to give you that respect and gets angry at you all the time, it might be best to find someone who is kinder to you.