Your test are not accurate. Oral sex exposes you to gonorrhea, syphilis and herpes. You should test as follows:
-3 weeks after the encounter, for gonorrhea.
-6 weeks after the exposure, for syphilis.
-3 months after the exposure, for herpes.
Don't really worry about HIV, as the risk through oral sex is negligible if you gave it and zero if you received.
All the best.