Hello and welcome to healthcare magic!!!
From the symptoms mentioned and considering the age group i would suggest you get a blood work up done including a complete and differential blood count and for the time being give her symptomatic relief by giving her antipyretics like paracetamol
and also make note of any bleeding from the gums or any small red spots on the limbs
. you can either get back with the blood counts here or consult a paediatrician who would guide you later on.