I have been experiencing the same sort of headaches, seems to be triggered when I am trying to keep up with my water intake. Most of the time I am able to go with out drinking at all, I have been off of fizzy and other sugary drinks for almost a year. So my water intake has become more necessary. I seem to get a bit of a pounding headache, almost feel like my brain is dehydrating. As I am writing this I can feel my headache. Taking in deep breaths in cool air and trying to relax my body seems to be helping. I do have the window open just so I can get the fresh air circulating too. Maybe give that a go incase it works for you too. If you are trying to lose few pounds Water diet is amazing and there's no need to starve. I definitely recommend it as I have given it a go and I had lots of comments regarding my skin and the few inches that seemed to become less obvious. It works wonders if you can try and fit in at least 8 glasses. Start off your day with 2 glasses if you can and pace out always at least half hour before food and everytime you feel pekish or snackish. Light exercise as in stretches in the areas you want to lose, planks, pushups, sit ups and squats. Good luck and hope this is helpful !