OK. May I start by bawling you out? If you think something may be wrong, you go to a doctor and, unless there is a good reason, you follow his/her advice!! If a doctor prescribes an antibiotic, YOU TAKE IT ASAP AND KEEP TAKING IT AS LONG AS IT IS PRESCRIBED FOR. If you don't take it as soon as possible, the infection that the doctor has diagnosed can get out of hand. If you stop too soon you can end up with an infection that is resistant to antibiotics. Not good.
It is possible, but not likely, that you have bladder cancer. Why not likely? Usually it appears in much older patients...not always. Your symptoms are not typical. This does NOT mean you don't have it...it means that you need to go to a physician and get a real diagnosis of what the trouble is.
It can be dangerous to try to diagnose yourself. You may have something very treatable and spend a long time suffering from it, and you may worry about things that are unlikely...ie, bladder cancer. Or, you could have something serious and waste valuable time dithering about it. I had a relative with a bad sore in the back of her throat. She refused to go to a doctor since she was afraid it "might be cancer." Well, it was. She lasted about 5 weeks after it was finally diagnosed, much too late for treatment.
My advice? Get yourself to a real doctor and get whatever it is taken care of.
Best luck to you
Sara Anne