March 23rd was my first ever sex encounter. Although I stopped him midway before anything happened. I stopped him before the tip of penincould even enter my vagina because I was scared and obviously Would be the first time something would be up there. We ended up just rubbing our parts, and I'm completely positive there was no cum and penetration. It's been 12 weeks since that day and my period is now 7 days late. I've had 3 periods since the incident but they've been either lighter than usual or came early. Could they all have been implantation bleeding and I was calling them my period? I've Taken over 20 pregnancy tests and they've all came back negative.