Starting friday evening, i've been feeling nauseous with an upset stomach and headache. i've tried eating/drinking fluids but nothing has helped.

See below: Wait twelve hours, then try clear fluids.

Stomach Flu: If you have pain or a fever this may be more urgent. But, the flu can last three, five, or seven days. As long as you are staying hydrated and have no fever or severe pain you will most likely just be fine.

Viral illness: It sounds like youre incubating a viral illness or the flu. Try a bland diet, nothing greasy or fried. No milk or juice. Drink non sugared fluids so you dont dehydrate.