Is 2 week appointments normal at 26 weeks?

Katie
I dont remember starting them this early with my 1st i remember being later than 30 weeks. My doctor seemed worried about my measurements and wants another ultrasound to check babys weight should i be worried? My 1st was born at 35 weeks and 5lbs 7oz and that's not too bad but i get shots every week so this one stays in longer.