A.G.
I had this too. I bled for almost 4 months, but not consistently. I would think it had FINALLY stopped and alas, there it would start up again. So, I think it is totally common so long as you are not soaking pads.
I too had periods while breastfeeding, although i didn't get my first one until 8 weeks postpartum, it's entirely possible that what you are experiencing is a period.
Good luck to you and I hope this makes you feel a bit better.