Thanks for the input, Agonycat. I know it's not dehydration--I drink water like it's going out of style. I do suffer from allergies from time to time, and have been a little sneezy this week, but I don't recall ever having been light-headed, downright dizzy actually, because of them. The room truly was spinning later in the evening. Also, I'm eating plenty of calories, around 1800 a day, and 20 to 30 grams of carbs a day, comprised of lots of veggies and protein and good old fat. I have noticed I've been running to the bathroom more over the past two weeks than I had been, so maybe if I keep up the potassium supplements and start using salt, things will even out.