What Causes Continuous Spotting After Taking Deviry?

Hi Doctor, I got my period on 15th of July, which was only for one day and later i consulted doctor, she gave me deviry 10mg for 3 days from21st of July till 23 of July...she told me that i wud get my period after 3 days of stopping the pill. On 30th I had spotting and it is still continuing till today...please advice if I its ovulation or any other issue