Hi, to answer your question, you don t seem to have a kidney infection based on your symptoms mentioned, however if you feel a burning or pain sensation while urinating it could mean a UTI. But an occasional diarrhea and nausea is common following ingestion of an allergen. You are probably allergic to those oysters and must avoid them. If you do continue to have frequent urination with discomfort while urinating, or signs of fever, you must see your doctor immediately to rule out a urinary tract infection.