Could Fatigue Be Due To Low Blood Sugar And Blood Pressure Levels?

I went to the ER yesterday because I had fainted during PE, and this has happened to me before when not doing physical activity about a month ago. The doctor said I had low blood pressure and low blood sugar, but it wasn't anything to worry about. I had an EKG, and the doctor said not to worry about anything neurological because I have already had an EEG and an MRI of my brain. My dad insists that I get my pancreas checked out in fear that I may have diabetes. I have always had digestion problems since I was young, but feeling faint is a recent problem. I am unsure what to do, and I don't know whether to be afraid or not. Please help?