My Period Dates Were 28th Feb N Today Is 3rd

My period dates were 28th Feb n today is 3rd Apr n still I m not down.I have adenomyosis n usually my periods are regular since 7 months. Plz advise how to get periods as I have family function on 8th Apr. Shld I do pregnancy test first n then take prepone medicine which u advice ? If pregnancy test positive n i do not want to b pregnant, how to proceed