i am on the pill and started the new pack 10 hours late and had sex the day before i took it late, from then i started to take the pill normally at 7pm everyday and never took it more then 30 mins late or missed another pill. my period is due between today (19th august) and the 20th august. when i woke up this morning i had some light bleeding when normally it is very heavy on the first day, do i have my period or implantation bleeding?