I am experiencing this exact same thing right now but am not hypoglycemic.
For 5 weeks now I ahve had a pressure in the back of the head, headaches and constant wavey feeling (vertigo) to varying degrees. Some days I ahev not been able to get out of bed while others I can but am very tired and dizzy throughout the day.
I have had an eng (ear, nose and throat Dr.) , mri, mra and seen a neuologist. Evrything is normal but I am still spinning. It is really beniginng to impact my life as I travel for a living and have not been able to for awhile now but the bosses are getting pushy.
I wish someone could give me a diagnoses and some help for this. I just started vestibualr rehabilitation but so far no improvement.