I am an 18 year old female. 5 3 and 150lbs. For the past 2 weeks I have been feeling very nauseas and throwing up after eating or drinking snacks/beverages with sugar. After drinking half a can of soda or having a 2-3 cookies will make me sick. I also get light headed after and feel a little off balance during. Diabetes does run in my family, but I got blood work done about 3 to 4 months ago and they said I was OK. What can it be?