I've wondered at times if it's just my Circadian rhythm wants to be nocturnal, or close to it. It isn't something that used to be the case, but I'm wondering if it can change, and that's what started to happen to me these last few years? My biggest issue is that I *need* to be functional in the same hours that my husband and the household is, so I can't really give in to it. Especially since we have only one car, and whenever I need it I have to be the husband's ride to work, heh.