Implantation bleeding or cycle regulating?

Kay

So I am currently almost 13 weeks postpartum and I had my period 18 days ago <a href="https://play.google.com/store/apps/details?id=com.glow.android.eve">Eve</a> says I’m in my “fertile window” and my fiancé and i had a condom break on us yesterday🙃 I’ve never had that happen before and I woke up this morning with this in my underwear (also I NEVER spot I didn’t even have implantation bleeding with my son) is this my period going back to normal or implantation bleeding? And this is all that came out I’m not bleeding anymore now so I’m really confused😅 I can’t afford plan b or else I would get one🥲 I’m supposed to be going to get birth control at the end of the month