I don't know if I'm pregnant. Taking it?

Around April 2. I had protected sex. However, afterwards he removed the condom and we continued to lay against each other. I have heard stories of women getting pregnant when sperm is near their vagina. I did not take Plan B after this happened. I was suppose to get my period about a week later and never did. At this point, I had taken four pregnancy tests and they all read negative. I have been under extreme stress since the day after it happened up until now and im not sure if that has a contributing factor in all of this. Then about 10 days ago i had unprotected sex but he ejaculated outside of me. I am not on the pill and immediatly went to the store an hour after the incident to take Plan B One Step. At this point, I am now 10 days late for my period. However, I feel my vagina/ lower muscles pulling and I my breasts are slightly sore. I read these could be symptoms of pregnancy.. menstrual, or plan b side effects? Can i get plan be side effects from plan b 8 days after taking it?