I had exactly the same thing happen to me. I stopped PP bleeding at 5 weeks, then one week later (right after my 6 week check up), it started again. I wasn't sure if it was AF or lochia. I phoned my OB's clinic and the nurse said to just wait and see what happened and that it could be AF back already, but they didn't seem too concerned about it. Anyway, DD is now over 13 months, I am still BFing and I have not had another AF since! And no, I am not preggers either!