UTI... nurses?!

I just got over a nasty UTI that I believed turned into a kidney infection I had it for about a month and was in three different antibiotics. Since then I've been testing my urine quite frequently, tonight everything was negative except for this one tiny dot.... I have a urologist appointment in the AM but I'm really getting upset, this has really taken a toll on my life and relationship as well as being able to focus on being a mother. Any thoughts about why I would just have 1 tiny dot? Thanks....