Measuring behind at 30 weeks

Hello ladies- wondering if anyone has been told their babies are measuring small based on ultrasound and had everything turn out ok. My stomach has always measured right on schedule, but I had a scan yesterday and my baby’s head and abdomen are behind while it’s limbs are on track or a few days ahead. Overall, these measurements averaged out to about 29 weeks, but I am 30 weeks along. It was 36th percentile for estimated weight. I am most worried about the head, which was 1.5-2 weeks behind depending on the specific measurement. The doctors said anything within 3 weeks ahead or behind is normal, but I feel quite worried. They don’t want me back for another 3 weeks to check on growth again. I had a late term loss in my previous pregnancy(my first) and a previa with this current one (they told me the previa is not causing any growth issues and the placenta is fully functional) so I am very on edge and just having a lot of anxiety about this news. Sometimes it feels like I may never bring home a healthy baby. If anyone has any similar experiences or insights they are much appreciated!