20 days late

I’m 20 days late for my period and I’m freaking out a little. I took a Plan B once and bled so means I wasn’t pregnant. Then AFTER THAT I had sex again, but the condom broke (he wasn’t inside me, but his dick was on my hole for a few seconds until he put on a new condom) I really have no idea how else I could get pregnant because we always use and check the condoms, except that time that it ripped. Could it be because of the Plan B from a month before this incident? I don’t have any pregnancy symptoms really... just my nipples are a little sore only when I touch them. Has Plan B done this to anyone before?