My PP bleeding lasted much longer than with Ivy, the weird 'yellow' stage lasted for 2 weeks - it is just finishing now really.
With bfing and AF really don't assume you won't be fertile because of bf. I know lots of women who got AF back at 6-8 weeks PP despite nursing constantly, no dummies, no bottles or formula etc.
The most common time for AF to return is around about the time food gets introduced or if baby is sleeping through the night etc.
In my case I couldn't get AF to return until Ivy was on one feed before bed when she was on the boob for about 3 minutes! I did fall pregnant before having an AF but that was a chemical pregnancy, I conceived Elodie 2 months later. So I have had 2 AFs since March 2010!