Sounds about right. Water more important than protein shakes at 4 days out. I find that room temp water is easier to go down than cold water. I keep bottled water everywhere I go. I have bottled water at home , in my truck, and at work.. 4 bottles a day is the recommended amount. Sometime I add those crystal light single packages to my water bottle when I am wanting something sweeter. I remember early on not being able to gulp water because it was very painful, so I would take a big mouthful of water and slowly release it down the back of my throat so it wouldn't be painful. As for the headaches, that could be dehydration too. Good luck and welcome aboard.