If it was food poisoning it could be anything - maybe you didn't heat the food enough, maybe you touched something with your hands and put them to your mouth...
You say you vomit with migraines. Maybe it was just a migraine. You know, I have noticed with this cleansing thing - whatever the health problem or symptom, when you cleanse it will escalate during the healing. I suffer from anxiety and when I cleanse my anxiety goes through the roof (temporarily).
I love the way you are thinking about the symbolism of your symptoms. Is there anything in your life that you cant bare thinking about? Is there anything you just cant stomache?