I feel the same way. I don't know what caffeine actually does but I'm pretty sure it keeps your skull from caving in.
As a New Year's resolution in 2007, I decided to give up caffeine and after getting past the initial throbbing headache and the constant temptation, I was able to make it to about mid-March before I began drinking pop, tea and coffee again. I've done a lot better in limiting my soda pop consumption but I need caffeine to survive.
