Woke up day 3 with a horrible headache!

More salt, More water? Could be electrolytes....I know that's what has been recommended to me with the headaches from ketosis. 3 days is typically when the body goes into ketosis in which it starts using fat verses carbohydrates for fuel. Certainly do your own research and/or call your doc if it persists.

Could the headache be related to caffeine withdrawal? I remember my pre-op diet having no allowable caffeinated drinks, and I had quite a headache for a few days, myself. Hope it resolves itself quickly for you! :/

Thanks for the suggestions! I drank some Gatorade and a couple sips of diet coke that seemed to help! I was fine day 4!