Hi Roots & Pirouette,
I'm thinking gastroparesis. Another friend of Lyme.
I found in an article (http://www.digestivehealth.com/information/patient-education/esophagus-and-stomach/115-gastroparesis)
Vomiting which occurs with food poisoning or intestinal flu may be a result of delayed gastric emptying.
You can get that checked by a gastroenterologist, they can do a gastric emptying study.
I have it, but it seems that it's better on some days, and worse on others. When I'm at my worst, I eat foods that digest easely and that are liquid or almost liquid, and I avoid fats, cause that makes it worse for me.
When really nauseous, I take Alizapride before eating, it works well.
Hope this helps as an indication,
MarieLS