4 Days Late, On Birth Control For 5 Years. Always Been Reg

hello, i just signed up on here b/c ive been google-ing all day trying to ready other posts of missed periods. here is my situation. im 21, ive been on birth control for 5 years, 28day cylce, always been regular...always... now, out of the blue i end my pill cycle and ususally start my period the next day, but got nothing, not spotting, no discharge, no NOTHING. Now its day four with exactly nothing. what do i do? too early for a pregnancy test? if sunday rolls around and still nothing, do i start my new pack!? Knowledable people please respond!

samantha