HELP ME think of something ladies

Okay ... I've been having irregular periods for 11 months now I went to the doctor about 2 months ago to ask to get put on BC pills because my mom said that if you have irregular periods just ask your doctor to put you on BC pills so I asked my doctor but I didn't tell her why I wanted to get on the so I got examined and stuff and she told me since I haven't have a period in 9months (take 2 months off) I couldn't get them they just gave me a plan B pill and some condoms then she said I might have PCOS which would explain the painful abdominal pain that was worded than cramps so like almost a month ago I had unprotected sex and I don't think he pulled out so I took the plan b pill like 2days after my period started but it was heavy and lasted longer than the normal 3days and I was happy cause my doctor tried to say I had PCOS and that can delay your period so I think the plan b kick off my period for this month but I'm worried it want come for the month of Dec what should I do?