I have this sometimes as well. I feel hungry and I know it's time to eat but all food makes me feel sickish and is totally unpalatable. Sometimes I look at my cooked food and feel repulsed by it! I know it must be psychological.
I keep simple beef jerky around and will nibble on that with lots of water. This will sometimes spark my hunger and let me eat my planned meal, or satisfy me if I eat enough of the jerky that I don't need anything else.
Well, I have trouble with this, but then again I'm prego. lol
Are you SURE this isn't your problem? You are a woman, right?
I go through this exactly when I've imbibed a bit too much... that + a headache is my exact hangover symptom. (not as much a problem anymore)
Water, multivitamin, and eating something protein + fat always seemed to do the best for me. Unpleasant, at least I know the cause and avoid it.
My recommendation: get your omega 3/6 balance fixed. Eat more veggies, big ass salads, cut down on overloaded fat (bacon!) and eggs.