Which day do I go by?!

So in April my period was two weeks early!! My OB said that so many factors play into a period starting and not to worry. End of April I took Plan B and my period came a week early (May 2nd). We are now on June 6th and AF has not shown. Can play b mess up your period? I don’t know if I go by my start date of last month, the 2nd or by my start date in April which was he 10th. No intercourse has happened but I am spotting