Welcome to HCM.
You are currently experiencing mild bleeding about a wk after period over.
If you took pills on regular basis on correct time without any mistaken,then you need not to be much worried. It may be due to some hormonal
imbalance. It is corrected in time.
Other thing, if your Bf ejaculated near about ovulation time,there is slight chance of conception even use of pill and bleeding may be due to aborted intrauterine conception.
So i advice you to do a USG lower abdomen for any retained bits or anything else and serum hCG
After that, you can consult with me or with your gynecologist for opinion.
Maintain proper hygiene and avoid stress
For more information,mail me....firstname.lastname@example.org