Hey ladies

So I had a doctors appt. Yesterday and they had said my previa isn't attached to my prior csection scar so that was a huge relief! But then they moved on to tell me my little girl is a week behind and in the 6th percentile. I must go in everywhere and get ultrasounds for the next 3 weeks and do a couple other tests, they had mentioned that smaller babies run a risk of stillborn and it just scared me and SO so bad, do you think they're being extra precautious and I'm over thinking it or is it that serious???