Suggest Treatment For Severe Back Pain, Fever, Nausea And Vomiting

Good evening doctor,

I have a history of UTIs and kidney infections. I am currently on long term antibiotics until a VCUG can be completed. That being said, today I started having severe back pain, fever, nausea and vomiting. I went to my Urology office and gave a sample which came back fine. I really think I have a kidney infection and am feeling absolutely terrible. Is it possible to have a kidney infection but a urinalysis to show nothing?