I had no idea until about 2 days ago that I had a untreated UTI. I went into the hospital because I had really bad cramps, a bad cough, chills and fatigue. I was told if I would have waited any longer, it would have developed into a kidney infection. I was prescribed antibiotics (500 mg of cephalexin). It started to kick in after taking it for 24 hours. Has anyone ever experienced a severe UTI like this? If so, how long did it take for you to recover?