I've had two bouts with a "36hr" like flu since October...
Having the pump made it alot easier than what I recall from my MDI days.
My body was clearly telling me "..if you try to feed me, I WILL hurt you and you WILL NOT like it!!...

". So I actually had nothing to eat or drink during the 36hrs, until that point in time came when I could tell I was i) hungry and 2) not going to regret eating / drinking.
As jen_slc states, since you are ill, your BG's will be higher, and insulin demands are thus also higher.
Kept a close eye on my sugars, and used only a correction bolus during the entire illness timeframe.
Keep an eye on your BG and keytones; I would drink only water if you can tolerate it.
Good luck. Hope you're back on your feet real soon..
PS: one of the Dr.Mom's I know, has recommended GatorAide as a drink when battling the flu. She says that you feel better after having it; we speculated that it must be something about all the electrolytes in that product. I know I will try it the next time I am ill. And having the pump will make the carb balance a lot easier.