text: why do i feel groggy when i wake up from a period of sleep? when i take a long (about two hour) nap, i feel groggy, lightheaded, and uncoordinated when i wake up. i hear this is normal, but nobody i know seems to have these sort of problems. what can i do/take to help relieve these symptoms, and why does this happen? you may be suffering from a medical condition that is called sleep apnea..  do you snore? heavily? if then, you might want to see a doctor as it could be serious. check out the website http://www.sleepapnea.org/ for more information whether this could be it...