M.G.
Not enough info to know what you are asking - how old is she, etc. Has she been checked out by her pediatrician - what did they say?
My kids pick up some bug every couple of months that doesn't usually go full force. The fever is to show their bodies are actually working to fight it off. They rebound quite quickly - but they will be tired until they do.
Pretty common. Is she in daycare or school?
We're not medical professionals - but as a mom, this wouldn't phase me.