Bubbly Sounds on Fetal Doppler

Callie • 👶🎀 8.18.18. 👶🎀 3.16.20.

15w5d and today, for the first time, I heard bubbly, swimming type sounds on my Doppler. I’m wondering if this might be the baby moving around, or if it’s more likely digestion related? It’s different than anything else I’ve heard thus far. Anyone else experienced this?