As you had an unprotected sexual encounter, it's important to let you know, whether you are having symptoms or not, all the STDs you have been exposed to. If it's trichomonasis or a simple yeast infection, they can be treated, but it would be also necessary to test as follows:
-3 weeks after the encounter, test for gonorrhea and chlamydia.
-6 weeks after the encounter, test for syphilis.
-3 months after the encounter, test for herpes.
-Regarding HIV, if you go for a duo/combo ag/ab test, it will be accurate 28 days after the encounter, but if you go for a normal antibodies test, it will be accurate 3 months after the encounter.
By the way, you shouldn't take any treatment without medical supervision.
All the best.