Yes it can happen because it happened to me while I was at my job a couple of weeks ago. I went to the ER because I was throwing up about 6 to 7 times a day and instead of gaining weight I lose weight and I was dizzy and had headache because I was dehydrated and my potassium was low.
I havent exoerineced it, but i read ot could be from dehydration or low iron, try drinking lots of water, and also ask ur doctor about anemia