Hi. I've had unprotected sex last week Aug. 24. We did a withdrawal method. A week later, on Sept. 1, I had a light blood discharge that only lasted for half the day only. I was meant to have my next period on Sept 2 but until now which is already Sept. 3, I still didn't have my period. I tried a pregnancy test but it was negative. I'm very confused and also don't want to have a baby yet just now. Can someone pls tell me if this is not pregnancy or if it is, what can I do to stop this.