Unprotected sex on 9/12, "period" came 5 days early; no pms or clots. keeps stopping and starting.neg pregnancy test 2 days ago. poss pregnant?

Tests are accurate: Home pregnancy tests are very accurate and not affected by foods, herbs, common illnesses, sexually transmitted diseases, or medications. A correctly done urine test gives a reliable result 3 weeks after sex (3 weeks after when conception might have happened) or 1 week after missing a period. If done sooner, a positive result is likely real, but a negative result may be due to testing too soon.