Missed pill

My birth control was late in coming in the mail a week. Did not have sex during that time. Once it came in I started taking it that Sunday I got it. Had sex on Tuesday and just to be careful we decided that I would take plan b the following day. Now two weeks later I’ve been crampy. I had sore breasts this past weekend. I have two more days of my regular pills before the sugar pills. Is this normal with plan b or should I be worried? Been taking my pills consistently since and have not had sex.