Vegeymom,
Colds and flu dont ususally hang on that long, unless your immune system is serioully comprimised. It sounds more like a food allergey, Perhaps to all the dairy. Most people think of lactose intolerence as just being a stomach ache and running to the bathroom, but it can give you that tired, achy, headachy feeling like the flu. After your fast, I would suggest to keep a food diary as you reintroduce different foods into your diet, and make notes of how you feel.