so sorry your little one is sick
first, I'd say that is could be a stomach thing, and the fever was the precurser, but also that getting the cake out was probably good (since you really don't want to increase sugar consumption when you're sick)
whatever the cause of the fever and whether or not it's a flu you should nurse her a lot. she needs to stay hydrated and flush this out and breastmilk is the best thing for that (don't buy into any pedialyte suggestions).
you don't mention how high her fever is, but as Colleen mentioned you want to pay attention to your whole child with a fever-is she listless, withdrawn or mostly like herself, but with a fever? my dd's typical response to any illness has been a fever-she usually shoots right up to 104 or so which was initially frightening but luckily in the few times she's been ill we hung back and let her body do it's thing.
the one time we tried to give dd tylenol she vomited it immedately, so if your dd's been getting it for 3 days and only now vomiting I'd think the throwing up may be from something else.
let her sleep, but follow your instincts and call your pede if you're worried.