Hey girl ...
No wonder you are feeling upside down, High School eh... I can't imagine what that's like there as we in England don't have High School ...
However, we had Secondary School 11-16 years old, then College if you want to progress to Higher Education ... but it's all scary, and I felt scared on my first days there. As long as you realise, your friends are probably all just as aprehensive as you ... so talk to them, see if they also feel the same way, go for a Coke and something you feel good to eat, be it a salad or even a Burger if you want it. You need to eat, if you are worried about your weight, then please please please eat healthily rather than not eat at all.
Ginger