Lately I've Been Having Sudden Attacks Of Extreme Dizziness And

Lately I've been having sudden attacks of extreme dizziness and sweating (I get absolutely soaked in just a minute or two), along with just generally feeling exhausted all the time. I know for a fact I'm not pregnant, I'm not old enough to be going through menopause, and this isn't due to extreme temperatures or stress (I'm in a very moderate climate and live a very calm life). The symptoms of sweating and dizziness usually last about 20-25 minutes, and I feel somewhat better if I eat (even though most of the time I've already eaten something BEFORE the attack). Any thoughts at to what this might be?