Ok so i had unprotected sex on the 6&13 then on the 16 i started bleeding and my period wasn't even supposed to have came on that day?

Pregnancy worries?: For fertile women who are having sex... it can be hard to tell if a woman is pregnant because some of the symptoms seen in early pregnancy can also happen in non-pregnant women. A home urine pregnancy test gives a accurate result. One can test about 3 weeks after sex (3 weeks after when conception might have occurred), 1 week after missing a period, or 1 week after starting a "weird" period.