Question!!

So I had my baby boy on November 9, 2018 and I breast fed him for two and a half weeks then I couldn't anymore. I went to the Dr six weeks later 12-19-2018 and we were ok to do the dirty or like we like to call excerise. Lol anyways we use protection and I started birth control but I have yet to start my period. I have been having this brown mucas discharge and like every so often have a little pink spotting...nothing to even use a pad or tampon. Any ideas?? Thanks!! 😁