Chances of being pregnant? Or plan b side effects?

Hi everyone, my boyfriend and I had unprotected sex October 13 and I was scared he might’ve came inside so I took a plan b pill a couple hours later. I got my period normal in November, the same week I was supposed to get it. I had to take a pregnancy test November 11 because I went to the clinic and it came back negative. I am now 12 days late on my second period and I have minor cramps but really sensitive boobs and I feel nauseous at times. I can’t think of any other time that there might’ve been a possibility of getting pregnant and I am really scared now that I may be pregnant. I have tried googling a late second period due to the plan b pill and it seems typical but I haven’t seen anyone post any side effects that they might’ve had. Has anyone else been in this situation?