I think I have determined a potential cause of my body's food rebellion. I noted that I was craving carrots (lots of beta carotene) and mangoes and oranges, and anything fruits or vegetables that are vaguely yellowish. So I looked up "beta carotene deficiency". It said "see Vitamin A deficiency." So I looked that up instead.
Results: dry skin, night blindness, increased susceptibility to infection. I haven't noticed any effect on my night vision, but my skin has been unusually dry for a while now. Also, from the Merck Manual, protein deficiency is an aggravating factor (so is celiac disease, but as I have been gluten-free for several years, this shouldn't be a factor now):
Secondary vitamin A deficiency may be due to inadequate conversion of carotene to vitamin A or to interference with absorption, storage, or transport of vitamin A. Interference with absorption or storage is likely in celiac disease, sprue, cystic fibrosis, pancreatic disease, duodenal bypass, congenital partial obstruction of the jejunum, obstruction of the bile ducts, giardiasis, and cirrhosis. Vitamin A deficiency is common in protein-energy malnutrition (marasmus or kwashiorkor), principally because the diet is deficient but also because vitamin A storage and transport are defective.
Further corroboration from looking up "marasmus" on the same site: "Electrolytes, especially potassium and magnesium, are depleted." I've actually been craving Gatorade lately. Normally I can't stand the stuff. This really sounds like I'm not absorbing nutrients very well at all. But if I was getting gluten-poisoning, I'd be very aware of it (nausea and fatigue are the most pleasant symptoms). So I'm not sure what's going on, unless I've just not been eating the right balance of foods...
So...looks like I'll be eating lots of veggies and meat for a while... also, I've started in on my multi-vitamin again. So maybe in a week or so, my body will stop rebelling. I hope.