Provigil. I don't ordinarily turn to medication as the treatment-of-choice for different psychiatric and medical conditions; but, if other causes for your excessive daytime sleepiness (i.e., your narcolepsy) have been ruled out, then i might want to suggest that you seriously consider taking Provigil (which stands for "promotes vigilance"). It might well prove extremely effective for you. Good luck!
Narcolepsy. Episodic napping can be caused by narcolepsy. Other symptoms would include sleep paralysis, cataplexy, and hallucinations occurring at twilight (transition to sleep). Sleep is typically non-restorative which can promote headaches. Other sleep disorders - including primary insomnia, apnea and restless leg syndrome syndrome - could also prompt excessive somnolence.