D.B.
The flu often is accompanied by aches and a fever but not necessarily upper respiratory symptoms like cough/sneezing. If she's in pain, keep up with the pain reliever which will also help the fever. You don't need to medicate a low grade fever, but this is close to 102 and she's achy, so by all means keep her comfortable.
Push fluids (water, jello, popsicles, maybe some watered-down juice) and don't worry about food. She needs the liquids more than anything. If she'll eat water-rich foods like watermelon or orange segments, great. Rest and sleep are great. When my kid was sick, I propped him up in front of the TV and put on a movie with the volume not too high. Half the time, he dozed off and then I turned it off. It was easier than fighting to get him in bed, and sleep is sleep.
The flu is usually viral so there's not much to do most of the time. Don't get upset if the doctor doesn't give antibiotics. They may test for strep even though she doesn't complain of a sore throat, and you'll have to wait for that result.
Sometimes we just never know what the name of the disease is, and it can run its course in 24 hours or it may take several days. Just give in to it and please keep her home from school so she doesn't infect everyone else. That's probably how she got it to begin with!