I don't know how true this is, but it sticks in my mind and will forever.
When I worked in day care there was a mom who worked at a hospital or doctors office. One time I took her son's temp after he woke up from a nap and he had a slight fever. She flipped out on me that you should wait about 30 minutes after they wake up to get an accurate temperature.
Just thought I'd share that.

I hope Hannah is better. And sleep is good!!!