My 5 year old daughter was swimming all day today and in the sun, it was really hot. Then after dinner, she complained of a bad headache and went straight to sleep. Unusual for her bc we still had company. She just woke up crying that her head hurt really bad, so I took her temp and she's running a 101.4 fever. I gave her some Tylenol, and She fell asleep almost immediately after. Should I be worried?