Nausea, Sweating, Dizziness. Relief On Drinking Water, Wiping Face. Due To Dieting?

Good evening, While working today after lunch I experience onset of nausea , and profuse sweat over my forehead , neck . I had to excuse myself and went to the bathroom. I felt I was a little dizzy. I also noticed my mouth to be extremely dry.I took deep breaths of air a couple of times, wiped my face and neck and had one pt. of cold water. I immediately started to feel better. It was scary. I have been dieting for about two weeks now. Have been under a lot of stress. Could this be the cause?