Delayed Period, Headaches & Breast Tenderness: Possible Pregnancy?

Question
 I AM SOON TO BE 28 YEARS OLD IN A COUPLE OF WEEKS.. I HAVE NO CHILDREN BUT HAVE HAD A  PREVIOUS PARTIAL MOLAR PREGANACY THREE YEARS AGO,  AND ONE REGULAR MISCARRIAGE AROUND SEVEN MONTHS AGO.  I NORMALLY DO NOT HAVE A REGULAR CYLCE.. BUT FOR THE LAST FEW MONTHS THEY HAVE BEEN REGULAR.  WELL I AM NOW 12 DAYS LATE, I HAVE HAD A LOT OF HEADACHES.. AND VERY TENDER BREASTS FOR A LITTLE OVER A WEEK NOW.. THE FIRST DAY OF MY LAST PERIOD WAS 4/5/06, I TOOK A HPT ON 5/8/06.. AND IT CAME OUT NEAGATIVE. COULD IT BE A FALSE NEGATIVE? THE LAST TIME I WAS PREGNANT I TOOK A TEST WHEN I WAS TWO WEEKS LATE AND BARELY SAW THE SECOND LINE ON THE TEST.. MY HUSBAND AND I REALLY WANT A CHILD.. SHOULD I NOT GET MY HOPES UP BEACUSE I DO NOT NORMALLY HAVE A REGULAR CYCLE AND THE SIGNS I AM SHOWING COULD ALSO BE PMS?

Answer
If you have a regular cycle of 28 days (from the first day of your period until the first day of your next period) ovulation occurs on cycle day #14. If your last period started on April 5, you were due for your period on May 2. The best time  to take a pregnancy test is seven days after missing your next period. Therefore the best time to take a  pregnancy  test is any time after May 9.