What Causes Severe Fatigue Along With Perspiration?

i have had three spells of sudden weakness in the last two weeks, that begins in the legs and then my whole body feels week, I feel clammy and perspiring. the first two times it happened it didn t last long. The last time it lasted about thirty minutes. I then felt sleepy and slept about an hour. I have been battling a cough for weeks now with no fever or flem. I asummed the cough is an allergy to pollen. Does this sound like a blood sugar issue? Thank you for your time, Terri My email address is YYYY@YYYY