I personally feel you need to gulp, and move on. Go to the music festival, don't just not go 'cause she's there, go there with friends and have fun. Don't go talk to her, if she is at all interested in the friendship or even more, she'll more then likely come talk to you. I know it's not easy, 'cause girls can be silly and some, which seems to be in this case, use love to easily, whereas they just know you like them, in which they abuse that (not being sexist, some guys do it too). I say, go look for some more girls, whether its at this music festival or not. If you see a girl who you find attractive, or looks like a remotely nice person, then pluck up courage and go talk to her, 'cause I'm sure that couple of seconds of fear will be much more comforting then having months more of anxiety with this current girl.
Unless, you go to the music festival (which I feel you should whatever happens) and she's like all over you, your feelings at the time might just run riot, and be like 'yeah I'll stick with her, I love her etc..' in which I say just think about what the situation, and reality, before you get straight into things.
Hope I've helped in some way... peace.