I don't know much about plan b, so plz don't make me feel stupid. You can take plan b within 3 days of you having unprotected sex, but will it make my period come earlier than expected? Cause I literally just got off my period today, I had sex with my bf, and now I'm seeing about buying plan b just in case. Someone please explain it to me and the side effects, if any, and how it works, and all that. Thanks.