this is quite normal when you start taking the pill. Especially during the first blister
Your next peroid might be slightly lighter than normal and you may, but you don`t have to, have some spotting or bleeding in between whilst your taking the pills - during the first 3 blisters.
don`t worry - unless the bleedig gets stronger or becomes odorous in whic case you schould go back to see the doctor who performed the surgery.In that case you might have an infection or rests in the placenta - the latter is very rare - so I would think the bleeding is just your bodies normal rection to starting with the pill. If you read the leaflet that comes with the pill you will find that spotting or bleeding is quite common. The spotting or bleeding usually has a brownish color..
hope you have a good recovery,