Possible UTI?

Ciara
Off and on for the last 5 days I have had the smell associated with a UTI when I urinate, but none of the other symptoms. It's doesn't hurt and I don't have the urge to go all the time. I've increased my water intake, but it doesn't seem to go away. There doesn't seem to be any rhyme or reason to when it smells, although, it has been worse in the mornings and gets better throughout the day. My doctor said its not a UTI because all the other symptoms aren't there. 
Any have this problem before or any idea what could be going on?