Go to the store and buy a quart of cranberry juice and drink it.
I'm not kidding - it is nature's cure for bladder infections. Also, continue to drink as much water as you can, this helps dilute the nasties and flush your system. For the time being, avoid caffeine and alcohol as those are harder on your system.

I'm not kidding - this has worked miracles for me. I never get full blown infections anymore because whenever I feel that tell-tale twinge, I take care of myself with the cranberry juice and the water.

(of course, if you aren't feeling better, see a doctor. )