This is a little bit off the wall, but are you using any sugar free gum or other stuff with artificial sweetners in it?

Xylitol is a sugar substitute that is in a lot of gums and other stuff. It is supposed to be safe in humans; however, in dogs, it fools the pancreas into thinking that they actually ate a big bunch of sugar. As a result, the dog puts out a bunch of insulin. The dog's blood sugar drops so low that he dies.

I don't use artificial sweetners because if they can kill dogs, I don't think that they are safe for humans. I knew a person that had severe low blood sugar problems. She constantly chewed sugarless gum. She quit and it got better.

This is probably not your problem, but I thought it was worth mentioning.

"Signs of toxicity can be seen as quickly as 30 minutes after xylitol ingestion in dogs. The xylitol causes a rapid release of the hormone insulin, causing a sudden decrease in blood glucose. This in turn may cause the following symptoms:

Vomiting
Weakness
Ataxia (uncoordinated movements)
Depression
Hypokalemia (decreased potassium)
Seizures
Coma
Liver dysfunction and/or failure"

http://vetmedicine.about.com/od/toxi...ylitol_tox.htm