Sinus migraines I know how to deal with: Take some excedrin or some other NSAID then get a wash cloth steaming hot and put it over your eyes and forehead to alleviate the headache ( if it cools heat it back up to as hot as you can stand), next drink some weak tea as the heat and caffein will help both your head and tummy, then munch on some saltines or dry toast as this along with the tea will help the innevitable upset tummy. Also a hot shower never hurts!
Now the flu only time can heal same with eyestrain, but right now I'm in considerable pain as all my nerves feel like they're firing all at once. Every touch of the skin and rub of clothing is exscrutiating. I'm actually laughing and crying I'm in so much pain right now! T^T