Sounds like you might be on the right track. I ran into someone else, on a lowcarb message forum, that is sensitive to fructose.

Fructose involves the liver have you had your liver checked recently? I think a CBC blood panel tests it.

Hmmm... now that I think about it, maybe I should have a few days of meat & veggies and no supplements to see if I can shake this blah feeling I've been wrestling with.

I know a group of people with a peculiar autoimmune disease do much better avoiding all starches (they test their food with iodine). It seems like maybe the human race really isn't evolved to eat constant sugar and starch all the time.