Help! I have recently had 3 fainting episodes and can't figure out why? They they are usually proceeded by slight nausea in the stomach then possible light headedness or a spacing feeling in the head and profuse sweating. Each time I have passed out for less then 30 seconds before regaining conciousness.

My doctor has done a blood sugar test which was normal. An adrenal (saliva) test was slightly low so he gave me some cortisol supplements. I don't know if this is it because I have had an episode since. Sometimes before and after these episodes I feel very fatigued.

I regulary exercise and never have an issues while excersising, these events have happened not only while standing but also in the sitting position. I have never had this problem before, it seems to have started within the last 6 months.