It probably seems like a hormonal imbalance caused by the birth control pill that is causing frequent and prolonged menstruation
You may consider taking tranexamic acid
and mefenamic acid
combination pills thrice daily for a week or so. Please get the pill prescribed by your primary care
If even after a week, your periods does not stop, then you require further investigations in the form of ultrasound of the pelvis. Management will depend accordingly.
I hope this helps you. I wish you quick recovery.