Help!

Is spotting normal 3 weeks after taking birth control pills?

I only take the progestin pills because I’m breastfeeding. I’m 2 months postpartum. As you can see in the picture I had my period only 10 days ago so I know it’s not that . I’m scared I’m pregnant again but I don’t think that could be it at all. Or is it just from having sex ? The hearts are from when we did