Measuring ahead by 6 weeks 😳

A couple things...this is my second baby, I’m not a small girl, and I have a long torso as well, I lost 10lbs in the beginning, and have only gained 8lbs NO gestational diabetes (I have been checked multiple times) With my first I always measured a week or two ahead. With this second baby at 28 weeks I measured 36 weeks, now at 31 weeks I’m measuring 37-37.5 while I don’t believe these belly measures are the most accurate to chart baby’s growth, I’m curious if anyone has experienced this and they delivered early?