Herpes causes painful ulcers once the blister bursts. I don't know what you have exactly, since you gave me a poor history and no physical exam to speak of. The clinic is treating you as a case of gonorrhea, not syphilis. It's a more logical diagnosis over syphilis.
The laboratory results are just gram stain results, and it just tells me that the specimen was properly collected and that it's not a staphylococcal or streptococcal (i.e. skin) infection. It has not yet eliminated STD. The culture and sensitivity results, which come out after 3 days, is the test that the doctors are more interested in, because it will most probably pinpoint what you have.