My neighbor found out that I took birth control pills

Today I experienced perhaps one of the strangest moments of my life. I went to the pharmacy, asking for birth control pills. At that moment, our neighbor from the neighborhood walked in and greeted me directly. I don't know if she saw me or heard me, but I was sweating profusely at that moment. I can't stand the possibility that she might have understood a topic I hesitate to talk about even at home. I mean, she might not have said anything either, but what do you think should be done in this situation?