Doc said ultra sound shows not enough fluid around baby....will everything be OK?

A year ago I misscarried twins GS 12wks 3 days and 12wks 4 days, I do not have any children.

I had an ultra sound done at 8wks 4days, I'm now 10 weeks along and just saw my doc at 9 wks 4 days....when I went in for the ultra sound the lady doing it said heart rate is good and gest. size was same as LMP 8wks 4days, she told me everything appears fine.....when I just saw the doc he said there might be a problem from looking at ultrasound....not abnormally low amount of fluid but not as much as they like to see....

My friends mom is a nurse that takes care of premature babies and she told me that this is a common thing that happens in this time frame in pregnancy and not to worry but almost everything that I read relates to poor kidneys/lungs and basically pregnancy failure...I'm worried but want to know from expierance, can any of you give me some insight.....will things be ok or should I prepair for the worst again?