Plan b 6 weeks pp side effects?

I never took plan b before. I was just about 6 weeks pp. Hubby and i didn't plan on doing anything but things went further than anticipated. Anyway we have 3 kids and we are beyond done. He has an appt for a vasectomy. I hadn't gotten my first pp period yet when i took it and i stopped bleeding 3 week's before that. Im just wondering about the bleeding. Its really freaking heavy and everything makes me nervous. My niece said that happened to her. Im just wondering if that's common And normal after taking it and how long it lasts. Im taking iron pills from all the blood loss after birth so that's why I'm so paranoid about the bleeding