Hi Worried Lady Thanks for getting in touch. You shouldn't feel at all ashamed, you are definitely not alone. And more importantly, you are on the right path to taking back control of your sexual health. Testing is the only way to be certain. A couple of things in answer and to help you manage your fears. HIV tests reach maximum accuracy at 12 weeks post possible exposure. So we would not recommend testing before the early December. It is worth pointing out that HIV is completely treatable. There is no change in prognosis for someone testing positive at 4 weeks or 12 weeks, so any delay won't be harmful to you. In the meantime, we would suggest barrier contraception as a precaution against onward transmission. This obviously will protect against all STIs, not just HIV. The last thing is about risk of infection from a single incident of unprotected sex with someone in the UK. Generally the likelihood of an adult male being HIV positive in the UK is about 3 in 1,000. The chances of a female receptive partner contracting HIV from a single act of unprotected sex with some one who IS HIV positive is just less than 1 in a 1,000 for vaginal sex, which rises to about 2 in 100 if it was receptive anal sex. So in all, it is extremely unlikely that you would have contracted HIV from this single incident. I hope that helps. Kind regards Gary Carpenter BioSure (UK) Limited