Hi, I am having pregnancy concerns. According to my fertilization calendar I was ovulating on September 4th and I not knowing this, had sex without his ejaculation (he did not stay inside me long and did not cum inside me). Since then, I had a one day period on the 18, 2 weeks after, which leads me to believe it was implantation bleeding. If it was, Id technically be pregnant right now. My period is 4 days late, it is the 22 and was supposed to start on the 18th. I took a pregnancy test on the day it was supposed to start but it was negative. Could I still be pregnant?? Please help