No birth control but....

Michelle

Not on any form of birth control. Period ended on 12/22. Had unprotected sex 12/24. Took plan B within hours. 12/30 experienced brown discharge. Also second day of ovulation is 12/30. Thought it was just a one time thing, but it’s continuously happening every now and then. No other symptoms.. is this a side effect of plan b? Or should I be worried about pregnancy?