Clean STD Results Leaves lots of Confusion

Patient: Today I just got my STD test results and was negative on all accounts. Before hearing these results I was 95% sure that I would test positive for at least one STD because I had discharge and experienced some discomfort while urinating. Now that I have received these results I am confused. Is there any other infection that could be causing these types of symptoms???

Symptoms: Discharge, Discomfort while urinating