Indeed, it’s something I think about quite a bit. The conclusion I’ve come to involves consent: If all people involved in something fully understand and consent to what is happening, then they should not be “judged” for it.
And yes, I know there are holes and loopholes in that conclusion, but I think it’s nearly impossible to have a logically sound and consistent moral framework.
Lemmy is not your doctor and you shouldn’t take medical advice from us. If it’s possible where you live, try to get in touch with a family planning clinic (or whatever the local name would be). They can get you some sti tests and give better advice than we can. You aren’t the first person to have unprotected sex, and you won’t be the last.