Jan, the way you've just described your afternoon: the slump of energy, the need for a boost, then the sugar crash, followed by an overwhelming exhaustion and need for a nap... well that is all in "the book" on sleep apnea. And it can lead to dangers for insulin resistance and type 2 diabetes as well, so please be careful. I used to do the same thing and have found that the CPAP machine is cutting the energy deficit down. Best hopes for you to get a successful treatment for your sleep apnea.