Uterus has a “full” feeling?

Makayla • Brantley’s mommy💙

For the past few days my uterus has been having a full feeling. Then when I look in the mirror I’m a little bloated. Also in these past few 3 or 4 days I’ve been cramping. They somewhat feel like period cramps. But the thing is, I’m no where near time for my period. I’m on cycle day 21 & according to my app it says I’m 6 days DPO? Does anyone know what this could mean?