The only risks for HIV in adults are:
1) Having unprotected anal or vaginal sex, or
2) sharing intravenous needles with IV drug users.
Protected intercourse, when the condom does not VISIBLY break, is no risk for HIV.
I'm not sure why you were prescribed PEP when there is no medical indication for you to be on PEP. However, I do not comment on medication prescribed by a physician.
Nothing you did put you at risk for HIV.
You have been prescribed PEP by a medical expert. While it’s true that the risks you take seem negligible at worst, the doctor obviously thought it was worthwhile.
PEP 24 hours after contact is very good. And will most likely prevent an infection. If your the anxious type about this then of course another reason to take PEP.
The modern PEP pills are generally quite well tollerated so probably mild to no side effects.
The downside of PEP for these types of low (no risk) encounters is the testing. Without PEP you can get very reassuring results at 4 week and conclusive at 6. With PEP this time scale starts from you finishing your course.
I’m not sure where you are from but in the UK you wouldn’t have been prescribed PEP for the encounter, especially because you don’t know her status. Most people do not have HIV. But that’s not a recommendation to stop.
Now you have started I’m struggling to find a compelling reason for you to stop. You have taken enough to obscure the testing timeline but not enough to have any effect on your HIV status.