You are only 16. The truth is that relationships at this age are not meant to last. You are supposed to learn what you can from this girl, and then move on to the next one and learn some more.
I don't think things are looking good for you at this point, and I think all of your "I love you's" and constant expressions of concern about your relationship are going to make you look weak to her, and weak is not an attractive quality.
I would suggest you break things off with her, but I know you won't listen. Therefore, I will say that the only chance you have is to keep your anxieties to yourself. She either will - or won't - break up with you, but if you haven't resorted to acts of desperation, at least you can walk away with your dignity.
Sorry, hun - it sucks to be 16, but it doesn't last forever.
Relax... I'll need some information first. Just the basic facts - can you show me where it hurts?