Period / PP bleeding

How do you tell if it's your period again or still PP aftermath ? It's been 3 weeks today, every trying cleared up to the point it was just the yellow discharge. Now I am back to bright red heavy (not to heavy) bleeding. Not big clots, but really small ones here and there. It's been s steady day at least now of this bleeding.. Period or still the aftermath of birth? I'm in no pain and am breastfeeding..