I feel like I want to vomit and my stomach hurts?

Plain and simple, if you aren't sick with a stomach virus, you're hungry! You may be dieting but you're going about it the wrong way. You're eating too little and sending your body into starvation mode. You should be eating probably about 1500 calories. Check with Calorie Count (caloriecount.com) and find out how many calories you should be eating for your age, height, weight. They will tell you how manty calories, what amount of carbs, fiber and so on that your food has. It's a great site, it keeps track of everything for you. Being a vegetarian I like to make sure I'm getting all the nutrients I need so between them and me we get it pretty close. Try it but for heaven sake eat something now and see if that helps. Something solid.