could be because of craneberry juice or could be because of some bacterial or viral infection.
Continue your antibiotic although ideally your doctor should have asked for a urine culture and sensitivity for your UTI.
Take plenty of water and continue cranberry juice.
Your diarrhea should be all right soon as there is no symptom of any bacterial infection.
If your burning urine continues even after current antibiotic course,get a urine culture done and then take the antibiotic,otherwise avoid unnecessary anti biotics.