Talk to Gynecologist on Prolong Bleeding

I'm 5months postpartum. In the recent menstrual cycle, my bleeding didn't stop. Consulted a gynac she prescribed primolut n (twice)and transamine 500mg thrice daily for three days. It's been 20 days now. The bleeding is in brown discharge form but didn't stop. Is this normal in postpartum phase? I'm actually worried now. What should I do more?