I bet you are scared peace! FYI - I just saw your post and thought OMG - I have to respond to this. 3 years ago I had blood in my urine- thats it. I was prescribed Bactrim. Felt ok for a few days and then WHAM - day three. I felt horrible - the worst PMS like cramps you could imagine...then headaches, then fevers, then swollen glands. Slowly after I stopped the antibiotics the pain went away. The doc just shrugged and said thats weird but no need for concern.
Fast fwd to fall 2012 and all hell breaks lose in my body. Turns out I have lyme disease. I had the bite, and the EM rash and lived in a hunting cabin. The blood in my urine (which did go away) was the first sign years ago. More likely it was a co-infection of bartonella or babesia which caused my herx reaction to the Bactrim (which I had taken before and not had a problem with).
I would look into babesia, lyme, and bartonella which can all cause blood in urine without an actual infection. By the way...no normal doctor will diagnose you with lyme or these infections. Nor an infectious disease doctor. Of course there are other things it could be too, but were it me 3 years ago I would want a list of the possiblites so I wouldn't have to go through the hell that I have been the past few months.