I live on the stuff, and if I do not drink at least the morning cup I too will get a headache and attribute it to just that. If I were you I'd try cutting it gradually, why torture yourself, right?
Over the years I drink so much I no longer get "energized"
Also you may want to have your blood pressure checked just to rule out anything. I have cut back a lot from drinking so much coffee since I do not smoke anymore, they went great together, ha!ha! Remember tea, and some cola's have caffiene too, so you may want to check the labels if you switch to something other than coffee.
Good luck with this
"darkeyes"