Breastfeeding & monthly cycle question

Blair
My baby will be 8 weeks tomorrow (April 17), and she's EBF. I have not had a period yet, which my doctor said was normal. Anyways, I started birth control last week, the hormone free pill (mylan). My question is, I'm starting to spot, I'm on week 2 of the pill....is that normal? I know it's not implantation or possible pregnancy because I haven't had sex since before my LO was born