There isn't a standard time frame. I'm assuming that by "sick" you mean vomiting. Once you are no longer feeling the urge you should start attempting to drink fluids. Start with Gatorade (or some other type of electrolyte replacement). You want to make sure to rehydrate yourself or else you will become more sick. Once you have kept the fluids down for approximately a couple of hours then begin eating things like crackers. Once you have kept that down for approximately a couple of hours then progress as tolerated. Like I said, there's no standard time frame. You just have to work your way back up to solid foods as tolerated. I would also suggest that you keep the foods you are consuming during the next couple of days limited to bland foods. I hope this helps!