First thing....slow down and take a deep breath!! You have NOT been diagnosed with bladder cancer yet! There are lots of things that can cause blood in the urine, especially in women....but your PC was very good to refer you to a urologist. Too often blood in the urine in women is ignored.
During your visit to the urologist he/she will probably do a "cystoscopy." This is a procedure where he will insert a very tiny camera into the bladder so that he can see whatever might be there. This is a slightly uncomfortable thing, very much like a pelvic exam at the gyno. Not bad at all.
IF he sees something suspicious he will schedule you for a biopsy of the bladder tissue. This is a similar procedure, although it is done under general anesthesia (usually an outpatient procedure) so that he can take multiple samples. These are sent to a pathologist who will examine them under a microscope. ONLY AFTER THE PATHOLOGIST'S REPORT IS BACK CAN A DEFINITIVE DIAGNOSIS be made. The urologist may have lots of experience and have a pretty good idea of what the diagnosis might be, but he/she cannot be sure without the path report.
Once the uro has the report, he can disucss with you whether or not you might have bladder cancer or something else, and set out a treatment plan.
Hope this helps. I do understand the panic you are feeling, but even IF it is bladder cancer, most cases are very treatable,.
Please let us know what happens! We care about you.
Sara Anne