It is extremely low. For your own protection though and for that of your next partner as well as getting over anxiety, some testing would be appropriate.
In 2 weeks, obtain a throat swab for Gon/Chlam; obviously must be a throat swab.
At the 12 week mark test for syphilis and Hep C.
HIV testing is not really recommended after an exposure of this nature, but may be useful to update your status at 28 days with a 4th generation DUO test - good to show your next partner a negative here!
Even if any of these were present, transmission through oral sex is a very low chance.
Very low chance of any STD/STI.
It may be time to update your status though so suggest:
- Chlam/Gon at 2 weeks
- HIV at 4 weeks (4th gen duo) no chance but good to know status
- Syphilis and Hep C at 12 weeks.