Our daughter has had a hard time with headaches lately.  Reading up on Juvenation.org forums.  Seems like people have headaches from highs or lows - depending on the person.  This is proving to be a bit of a moving target.  Seems to be the same time and place at school.  We're trying the holistic approach to supplement this.  What I'm finding thus far is that drinking plenty of water is a good first start.  Should probably have the eyes checked as well.