In the case of transmission through oral sex, the risk is at the lower end of the spectrum compared to unprotected vaginal or anal sex. You can definitely learn more about the specifics which may ease your mind through this article: https://h-i-v.net/transmission. The risk of transmission also varies based on the type of intercourse. The five fluids HIV can be transmitted through are breast milk, blood, precum, semen, and vaginal secretions (not saliva.)
Do you know the status of the person you were with? That can give you a sense for if you need to be tested and if so, I can provide some information on that, too. Just let us know. I wish you the best - Liz (Team Member)