Girls, hi! What were your feelings in the belly and uterus at 16-17 we…

Girls, hi! What were your feelings in the belly and uterus at 16-17 weeks? I don't feel any pain, but there's this feeling like something is elastic, like a ball... Is it just that the uterus is growing, or maybe it's a spasm? I lie down and twist myself. But every time I go for a gynecologist appointment, she says my belly is good and soft, and on the ultrasound, they said there's no spasm. But now for two days I have these sensations, I'm afraid that a spasm started?