Am I Being Paranoid?

Last night my boyfriend and I had sex with a condom with me on top. After he ejaculated, I stayed on top for a few minutes and then pulled him out and laid next to him. As he was trying to recover, I noticed that he did not have a condom on still. We both panicked and checked everywhere on the bed, then got the idea to check inside me. The condom was inside my vagina with the opening still outside of my vagina. I pulled it out and there was ejaculate on the outside of my vagina and down my legs. I cleaned up and checked inside my vagina and didn't feel/see any cum so we settled on taking Plan B today just in case. I took the Plan B but as I was changing for work, I noticed that my underwear smelled like ejaculate. I am starting to freak out that I may become pregnant because Plan B may not work as well as I am slightly overweight, plus the fact that my underwear smells like my boyfriend when I didn't wear this underwear last night. I cannot get pregnant, I am so scared that it is a possibility.