Measuring behind.

I am 28 weeks and 2 days with my first baby and I went to the doctors yesterday and took my glucose test and had my ultrasound done, and at my anatomy scan at 24 weeks my little man showed completely healthy and no abnormalities were found but he was measuring small, well I went in yesterday and he is still measuring small they say I am measuring around 26 weeks and that there is a little more fluid in the sac but that he is not to concerned with that he is more concerned about the measuring small fact so he is sending me to a critical care doctor for further testing and a more in depth ultrasound, I also found out today that I passed my glucose test but that I am anemic and my iron count is low. Did any of you experience this? I am just so worried for my little man. He currently is weighing 2 pounds and 2 ounces