Start drinking cranberry juice IMMEDIATELY. Chances are it's just a yeast infection, and drinking a lot of cranberry juice will change the pH of your urinary tract so that the yeasties die. You can find unsweetened 100% cranberry juice at the health food store usually. That is an allowed fruit drink even for candida people. But you have to dilute it in order to get it down because it is STRONG stuff.
Also get a tincture or tea of Uva Ursi. It's a great cure for bladder/urinary tract infections. For the irritation and pain, you need Marshmallow. It's very soothing and protective.
I doubt the p&b shakes had anything to do with it - more likely hot, humid weather is the culprit