Girls, good evening! Today all day is grabbing my stomach, by evening …

Girls, good evening! Today all day is grabbing my stomach, by evening it's straight stone-like, went to shower and after that nothing changed (although usually it gets better). And here's the question: could this be from yesterday's ultrasound or is it wonderful premonitions starting? I have a big baby for our due date and plus early placenta maturation. Thoughts keep coming up about giving birth earlier than expected...