Period after giving birth

Izzie • Mommy of a boy and three girls 👦👧🏻👶🏻👧🏼

I gave birth on April 2. I got my period on May 5. Today is June 25 and I still didn’t get my period again. I’m 18 days late based on the apps calculations. I took two pregnancy tests and both are negative. Is this normal?

I’m not breastfeeding.