16 hour fever

OK can anyone solve this medical mystery?

Kaylie has been whiny and clingy for about three day, and I'm thinking, oh great she is getting sick cause also she has been napping, which she does not do on a regular basis, remember now she is my night owl, and fights sleep all the time. So I picked them up from day care at 1:30 yesterday and we went to play at school, and when we left about 3 she was running a low temp, and was complaining of a tummy ache, and was tired, I forced some Motrin down her throat, and she took a nap. She ate supper, ran around for awhile and then her fever spiked again. Her dad put her to bed, after she refused more medicine at 10:00. She woke up at 2:30 Burning ( 103.8 temp) I gave her some Motrin ( she didn't have the strength to fight me) A half an hour later she asked to go back to her bed, and at 8:30 this morning she came to me bright eyed and bushy tailed, with NO FEVER and seems fine??