What is considered a fever?

Just took my 6 week old baby’s temp rectally. It was 99.5F — does she have a fever? She felt warm to the touch that’s why I checked her. She’s been laying on her belly on my chest for about 45 mins asleep with a somewhat thicker blanket on top of her. But it’s light so when she moves, it falls off of her so she’s not wrapped up in it. Just wanting to know if i need to call her doctor or if she is fine?