Period cramps but no period... wtf

I’m 14 weeks postpartum and since about 9 weeks I’ve been having really intense period like cramps but no period. I’m exclusively breastfeeding but my baby sleeps 8 hours at night without feeding. They’re pretty intense and are knocking me on my butt. Has anyone else experienced this. No I’m not pregnant I’ve taken two tests and it took me 4 years to get pregnant with this babe. So frustrated.

EDIT: I gave birth vaginally. No complications easy birth.