I have had similar experiences. i was labled with "visual migraines" it can come on with just visual stuff, and last from 5 to 60 minutes. Mine starts like someone popped a flash bulb in front of my face. I cant see past the dancing dots. I get clammy, cool, and feel weak as if I have been digging ditches for a week with no break, and no water. I dont feel like my legs will hold me up. I have had ON in the past, and since no sx of ON could be found, we settled on "visual migraines." really scary when it happens. I hope you feel better.