Im totally no expert, and have just umped into living Primally after reading the book/plan.
What I can tell you is this. I had a killer headache the first day, and I really thin it was my body crying out for carbs. In the past I would grab a sports drink, like Gaterade, or get some instant noodles, and that usually settled it down. This time, I totally refused to do so, hitting the water, and resting as much as I could. After the first night, the headache went away, till later that night, and again, I felt it was the urge for carbs that created it.
So far, I have gotten over that hill, and working towards a much more energy and fun filled days. Stick with it. I know the headaches can hold you back, on the third day, I took some paracetamol, and that helped stay on track. So far, I have yet to have another headache like it, sleep and naps help a lot.
Let me know how you go JennyE...