Please have her spayed.
Years ago I knew nothing of this illness, One morning I awoke to find blood & puss every wear, my dogs womb had burst, we almost lost her. A few years later, with another dog I recognised the symptom's & although the vet did not think it was pyometra, I ask for them to investigate & be sure, yes it was pyometra. So this time with Kez, my present dog, she was spayed right from the beginning as I only had her as a pet.