Took a plan b pill. my period was about a week late. i am now going on my 12th day of my period. whats wrong? could i be pregnant? will it stop?

Doctor can check: Taking Plan B or other emergency contraception pills can alter the timing or the quality of the current menstrual cycle and the upcoming cycle. One should check a urine pregnancy 3 weeks after taking Plan B. Twelve days is a lot of days, so a patient should contact her primary care doctor or Ob-Gyn doctor and discuss her symptoms.