Baby Movements

I’m 16 + 3 and I’ll sometimes feel what I think are flutters but sometimes they also just end up being gas bubbles. This is my 3rd pregnancy and I’m just a ball of nerves. Baby was measuring in the 30th percentile at my 16 week scan so trying to chalk up not feeling a lot of movements to them being on the smaller side? I do have a posterior placenta.

Does anyone have similar stories where they didn’t feel consistent movement until later? Just trying not to overthink! 😞