I would try adding some Jell-o to what you're eating--regular Jell-o, not sugar free. Drink Gatorade, again, regular, not sugar free. I'd also check how much you've been eating the last few days. You won't get fat eating chicken soup while sick! And you might be feeling like passing out because of low blood sugar if you haven't been taking in enough calories.
The time to worry about losing weight is not when one is sick, Lyn... I'm not saying go for the pizza and ice cream, but you do need to have some food...
Go to the doctor if you don't feel better soon...
Jay