By the way, the headaches you are getting are called vascular headaches. They are caused by too much blood being allowed to circulate through blood vessels in the brain, increasing pressure and causing a headache. Caffeine (as well as nicotine) have a capillary-shrinking effect on your blood vessels, making them smaller. Your body then adjusts. After a while, this size is assumed by your body to be "normal" When you stop drinking caffeine, the vessels are no longer the correct size, and a headache ensues.

Aslo, Advil will NOT help a vascular headache. Believe me, I tried.