Was your oral protected? If it was, there is no risk for gonorrhea (which is the clap) or chlamydia.
As long as the head of your penis is covered, you aren't at risk for anything except those that are transmitted by direct skin to skin contact, like herpes, HPV and syphilis.
Condoms offer a lot of protection, but not 100%.
Syphilis is uncommon in most developed countries, like the US, UK, Canada, and countries in Europe.
Don't take antibiotics you don't definitely need. That's why we have resistance to antibiotics now.