Implantation Bleeding & PP

I am 9 weeks postpartum and had unprotected sex 2 weeks ago. (Yes, I know.) The past 3 days I have had brown and very light pink spotting. I am EBF, and have not had a period yet. Negative pregnancy tests. The spotting has stopped. Could this be implantation bleeding? Or maybe just a slow start to my period?🤞🏼I did not have IB with my first pregnancy. (No, I am not trying to fall pregnant again, we shouldn’t of done it in the first place.)