I've been battling cold/flu symptoms ever since Monday, and I started taking generic Theraflu on Wednesday. Since then, I have noticed one major thing: I have been ravenous! And while the thought of food kind of grosses me out, I can hear my stomach growling, begging me for food. I googled something like "hunger while sick", and I discovered that one of the side effects of Dextromethorphan (an active ingredient in what I had been taking) is hunger. That explains it!
Normally I tend to eat less than a typical day while I am sick, but I actually ended up going over my calories yesterday because of eating due to hunger. I'm going to have to really watch this over the next few days.