Few months ago, I noticed that I was having discharge from my penis and it did not smell good. I got a urine and a blood test, to test for Chlamydia, Gonorrhea, HIV and Syphillis, which all came back negative. The previous time I was involved in any sexual activity was 4 months before that test (in which I only had unprotected oral sex). Since it came back negative, I decided to leave it thinking it is probably nothing. Now, I do not notice discharge as much but I have a slight burning sensation when I urinate sometimes.
Were my previous test results wrong? What is causing my symptoms, could it be any other STI?