For the last year or so I've been quite a heavy sleeper (wanting to sleep for 12+ hours a night) but I remember the night before going on holiday, I couldn't sleep till about 2am then woke up at 6am. It was so unusual for me, but it was because I was excited, nervous, anxious, all those feelings. It's only normal for a person to lose sleep when something rather big is happening in their lives, like starting a new school. And you did state you were excited/nervous, so that could explain a lot. Missing camp could be indicative of some type of sadness, which can also contribute to sleeping patterns being disrupted. I take it you have trouble getting to sleep and staying asleep, correct? That shows signs of insomnia, but I doubt you have a serious condition. My suggestions for you are to go for a run or do some type of exercise before bed. This tires out the body and when you hit the bed your body is more inclined to relax. Also, try having a hot shower before bed, followed by a warm glass of milk or chamomile tea. You could also try putting a few drops of lavender on the underside of your pillow (I've heard this helps).
Listening to music helps some, but for some others it wakes them up. It gets their brain working and makes the body/mind alert. I think probably avoid listening to music for a while and see if that changes things. Reading a book before bed can also make your eyes heavy and tired. I'll add my two cents about sleeping pills, because sometimes they really do help. They basically relax the body and allow it to fall asleep, which could benefit you greatly. You could buy some herbal, over the counter sleeping aides, which are fairly cheap, but if you wanted something stronger you can head down to your doctor and talk to him. He can suggest some other possibilities too.
At the end of the day I think it comes down to stress, and being able to turn your mind/body off. Wear it out before bed and I hope it helps a bit. Good luckkkkk.