Belly movements anyone? Not due to pregnancy

Miri
My daughter is a year and one month already, I am currently not pregnant and on mirena birth control for like 4 months already. Was also tested for pregnancy before i got the IUD .but I keep feeling these strange movements around my belly area, sometimes in my sides too. I asked the doctor when I was getting my mirena and she just laughed and said " I miss being pregnant" which uhh, no. Beautiful moments and all, but, no. There has to be a reason to it. So please anybody out there experiencing the same feeling?