why cant i sync my ipod?

I plug it into my computer and go to itunes but i cant click the button that says "sync ipod" in the file drop down menu.

the funny thing is that usually when you plug in your ipod, the screen should say "do not disconnect" but it doesnt do that. it just starts charging but the screen doesnt change.

did i break it? did this ever happen to anyone? how the heck do i fix it?