Heavy implantation bleeding 6 months Post partum?

I breastfeed. Baby boy still not very interested than eating (swallowing) more than a few bites of solids... so he still nurses regularly (2-4 hours between). Since 8 weeks PPartum I have had regular periods of 8-10 days. Starting heavy and bright red then gradually becoming lighter and brown. This month, 6 months PPartum, my period was heavy and bright red for 3 days... then just stopped completely. No blood at all! What is your vote? Body out of whack or maybe heavy implantation bleeding? (We are not using protection till the end of our intimate interactions...so Not trying, but not totally trying not to get preggo..lol)