"already posted about my side effects from the pill but that was before i got my period so i wanted to share the rest of my experience. did not get my period until exactly 1 month after taking plan b. had a terrible headache and nausea all day, which isn&#039;t a common pms thing for me. it was 2 weeks late! i know it&#039;s hard but don&#039;t stress, it will do weird things to your body. good luck!!"