Where is my butt going?!😱

Chanel • 💕31 year old 1st time mom to be💕
I'm a curvy female and I've always had booty but my butt is getting smaller. My bf asked me this morning, "why are u shrinking? I thought it's supposed to grow"... I didn't tell him but it made me feel insecure. Hellllp! Has this happened to anyone??