Bleeding

I’m breastfeeding. I had a very heavy period at 6 or 7 week pp. it lasted 8 days. Didn’t think anything of it being the dr had recently checked me back that and said everything healed. Started my bc (the pill) after been on it for almost a week and today I am spotting. It’s not pink it’s kinda dark like my period but I got my period so I’m confused. I also just finished an antibiotic that said it could effect my bc. Idk if that has anything to do w it. Is this normal? Or should I call my doctor?