i hope i shouldn’t worry?

i’m on cd 12 and i just got my normal period back after i took emergency contraceptive pill 2 months ago on October 10 (got false period after it). For some reason there’s a small dark brown spot near my left areola that is making it seem like my areola is expanding. but i can’t be pregnant after my period right? This is most probably my mind playing tricks on me? Can someone please help me?