had period on 14 jan, next due on 12 feb, but no periods, and no intercourse between

WE ARE TRYING FOR BABY.HAD REGULAR SEX BUT DISAPPOINTED TO HAVE PERIODS ON 14 JAN.SINCE THEN WE WERE NOT TOGETHER.I EXPECTED PERIODS AROUND 12 FEB.BUT IT NOT ARRIVED YET.WHAT COULD BE THE POSSIBLE REASONS.CAN I BE PREGNANT? PLS HELP