Bc and late??

Hey ladies need some advice I just got off birth control the last week of February and had my normal period starting March 2nd. I was supposed to start Sunday and have yet to start back hurts at times and very tired and have a clear heavy mucus. I took a hpt yesturday and today and both negative. Could my period be late do to getting of birth control or could I be pregent? Has any body been late after stopping birth control?