Bladder infections sometimes move up the urinary tract to your kidneys, which is more serious. Or you can get a kidney infection after surgery. You might have fever, chills, nausea, vomiting, and pee that’s dark, cloudy, bloody, or bad-smelling. Your doctor will likely prescribe antibiotics to treat the problem. But you can try to prevent it, too: Drink plenty of water, try to pee after sex, and go when you feel the urge.