Something else to consider is environmental factors. Lots of scented products kids sometimes go crazy for, poor ventilation in a portable classroom, florescent lighting, etc? Just another thing to consider (as a teacher I've heard stories from colleagues about getting very sick transferring into a new school with mold problems and I personally felt sick in my Spanish class in high school at the edge of school and I finally figured out kids were smoking behind it). But it does sound like stress and possibly diet.
