Extremely Scared/Nervous. Please Help!!

I had unprotected sex with my boyfriend on November 13th. We used the pull out method & something went wrong & I took Plan B the same day as the accident. I'm supposed to get my period on the 22nd, but I am irregular & it usual comes 3 days after my last period (my last one was on the 19th of October). Usually before my period my breasts will hurt but they haven't at all this month. I'm really starting to get nervous. Can anyone explain this?