Originally Posted by Natalie_ca
Light headed = greying of vision, ringing in ears, dulling of hearing and a feeling like you are going to pass out. This is the feeling we sometimes get when we go from sitting to standing too fast.
Actually that's not "light headed" that's referred to as pre-syncope and can have many causes other then dehydration. I experience it due to a combination of blood pooling in extremities, low blood pressure, low blood volume, and a faulty ANS. Neurological and heart problems can cause it as well. Migraines can start out with similar symptoms in some people.
Dehydration isn't the soul cause of low blood volume either. Some individuals kidneys don't work how they should. Thick blood - certain genetic clotting problems, and blood loss are the other obvious causes.
Since this is a sudden occurrence it could be from a cold. If it keeps up get it checked out with a doctor.
And I agree, don't drive. Certainly since this is new and you do not know what the "normal" progress of it is - if it truly is pre-syncope you could go on to experience full loss of consciousness, being a huge danger to yourself and others.