I have been eating tons of fruits, veggies and some protein for a few weeks now, but no breads or sweets. Last week I had a couple of slices of pizza for supper, and was dizzy the next day until about 2 pm. Last night I had a slice of toast, and today I was dizzy until about noon. Is this an allergy , a blood sugar spike or what? Why would the dizziness last so long? My blood sugar was normal last time I was tested.