I had my 28 appointment today heartbeat was 135 and my belly measured correctly but we discussed my…

I had my 28 appointment today heartbeat was 135 and my belly measured correctly but we discussed my ultrasound from 2 days ago ( growth ultrasounds due to marginal cord insertion ) doctor said baby is measuring small 8th percentile which is expected with MCI but it still kind of concerns me anyone else have a baby measuring small ? Starting Monday I meet with the high risk doctor I also start weekly NST tests and ultrasounds. My first pregnancy was a breeze this one has me worried I just want him to make it here safe and sound and healthy !