My first SW CAH boy went to a daycare for about 10 months, my Ped. told me, after he was sick a lot, to move him to a smaller daycare, 4 or fewer children or do a nanny. There are lots of germs at daycare centers, passed around and around. Your granddaughter is probably just catching everything that is going around. I would though check and see what is "causing" the fever ie. ear infection, bladder infection, could be just a virus. You do need to double or triple the medication depending on how high the fever is ...
Good luck.