What Causes Heavy Bleeding After C- Section?

hi,
i am using regestrone as i am suffering from heavy bleeding after my second c-section. doc prescribed me regestrone 5mg for 21 days.3 tablets each day for one week,2 tabs per day for one week and one tab per day for one week. i am using them and this is my seventh day,still my am spotting some blood droplets.is that ok or i need to consult the doctor