I was taking some sort of standardized test for math in first grade when I started having trouble focusing and fell behind. My teacher, seeing that I wasn't in the same section as the rest of the students, told me not to skip ahead. Then, near the end of the test she saw again that I wasn't in the right place (I think I had actually not advanced more than a few problems beyond where I had been before) and realized that I was actually behind. Knowing that was not like me, she sent me to the nurse's office, where she (the nurse) verified that my blood sugar was low.