I have these episodes occasionally where I suddenly feel very sick to my stomach and lightheaded, and it is very intense, then suddenly, usually within an hour or two, I am fine but a little weak. I went to my doctor who did blood tests, the only thing abnormal was low Vitam in D and a Glucose level of 63. THe doctor said not to worry and to just eat a bunch of small meals in a day and take vitamin D. I have. Today I had a bowl of cerial in the morning, some coffee (not much cream and very little sugar) and had some applesause a few hours later. I just went to eat lunch, was fine, sat down, suddenly felt absolutely starving, then just as suddenly I was dizzy and nausiated, weak, and my back even hurts. I tried to drink some coke or eat, but that made it worse. I am now, an hour later, not feeling it so acutely, but lightheaded and my stomach hurts, and my back on my upper left side below my sholder on my ribs is killing me and I am very tired. What can I do? Am I not eating right still? Could my doctor have missed something? It comes like a giant wave but receeds in small waves, wher eI feel fine, then bad, then fine, then bad but each time the bad is a little less bad. I am 30 years old, not overweight, and just was checked by the doctor with only the two abnormalities.