STD's fall into two categories, like any infection- bacterial or viral. The bacterial ones, like gonorrhea and chlamydia are easily remedied and cured with antibiotics and you usually get the symptoms quickly enough to not even get tested, more like you have it, you go in, get it checked out, get it situated.
The viral ones are a bit more tricky and most likely wouldn't even show up on any tests, if you choose to get tested now. Viral STD's could take months to manifest themselves, sometimes even years. The viral ones like to bury themselves in your system and can remain hidden for a good, long time. Did you know that herpes doesn't show up? And that the average time for HIV to show up on any tests is about 3 years? Yeah, people with HIV had it for THREE YEARS before it showed up on any tests.
So get tested if you want, but don't be surprised if nothing shows.