I took an emergency contraceptive in february. my march period came early, but my april period is currently 4 days late. is this a normal side effect?

Morning after pill: Emergency contraceptive is about 95% effective if you take it within 24 hrs of unprotected sex & 85% within 72 hrs. It can cause abnormal bleeingd for 2-4 wks after. I would recommend a pregnancy test to make sure you are not pregnant and If you are not, talk to your doctor about options to prevent an unplanned pregnancy that suits your lifestyle.