HI MY PERIOD WAS DUE THE 26TH OF APRIL 2007 AND I HAD SEX ON THE 20TH OF APRIL I HAVE TOOK A HOME PREGNANCY TEST AS I AM 3 DAYS LATE THE TEST SHOWED NEGATIVE I HAVE HAD A FEW LIGHT CRAMPS BUT NO PERIOD I AM VERY EMOTIONAL THE LAST FEW DAYS I CANT EXPLAIN HOW I AM FEELING HOW LONG AFTER SEX SHOULD I WAIT UNTIL I TAKE A HOME PREGNANCY TEST?