Fetal growth dropped from 11.7 to 4 centile.

I am 29 + 6 weeks pregnant. Estimated fetal weight is 2lbs 9oz. Fetal growth is at 4 centile. Abdominal circumference is at 5th centile. Amniotic fluid volume and dopplers are normal. Is this IUGR? What should I do now? I am really worried.