Please do not be depressed. Cancer does not present this way.
It is the residual component of the infection in the lungs and the UTI that is causing the fever
. I hope you have taken effective antibiotics for the same.
Take simple anti-pyretics like Dolo
650mg thrice daily for about 3 days. Drink plenty of fluids orally. You should be fine soon.
Hope this alleviates your worry.