IS THERE ANY PROBLEM IF YOU HAVE ONE PERIOD OTHER THAN PREGNANCY THIS IS WHAT HAPPENING WITH ME ....

HI,I AM 30 YRS OLD I HAVE A PROBLEM FROM LAST THREE MONTHS I USED TO HAVE MY PERIODS JUST FOR TWO DAY ON 16 TH OR 17TH OF EVERY MONTH I HAVE DONE MY PG TEST WHICH USED TO NEGATIVE EVERY MONTH.IS IT ANYTHING TO WORRY ABOUT N ITS A HEAVY BLEEDING ON FIRST DAY THEN LIGHTER ON NEXT CAN SOMEBODY WILL HELP ME WHO IS SUFFERING FROM THIS SAME PROBLEM.N I AM TRYING FOR BABY AS WELL.WHAT DAYS SHOULD I TRY SO THAT I CAN GET PREGNANT.THANKYOU