And BP always below avg. Have you tried drinking juice or gatorade instead of water a few times per day? It is possible to be over-hydrated and low on sodium/potassium, which can also cause headaches. Sorry, I don't have better advice. hang in there and take as many breaks to put your feet up and close your eyes as you can. Maybe tell your Dr at your next PNA...but I know you work with Drs so you might have already done this.