What Causes A Constant Urge To Urinate?

My daughter last week had the urge to pee but nothing would come out she said. Had a UTI test done and came back negative. She is still having problems and I've been keeping track of intake and outtake for couple days. She will go 100mL then 10 minutes later going 5 mL then going 10 minutes after that and only 1mL. Her urine is dark yellow, smells, cloudy and has thing floating in it. What could this be if not a UTI? What else needs to be done?