Ugh, I'm sick too!
Hoping it's not the flu, but it has been going around here.
As far as I know, most of the rebound weight from fasting is water weight due to carb consumption (this also where initial losses come from). A little bit of it is the actual weight of the food in your digestive track. (Obviously the other avenue for rebound is straight up overeating.)
So if you don't want the numbers on the scale to jump all at once, add carbs back in slowly.
Personally I would just go back to dieting/eating as per normal and not get back on the scale for like a week, until all the water fluctuation had settled down completely. Take care!