About to get my blood drawn finally! I'm starving! I saw my doctor and she said she's worried about…

About to get my blood drawn finally! I'm starving! I saw my doctor and she said she's worried about me not getting enough nutrition since I'm not gaining any weight. I've lost a few ounces in a few weeks but I'm also maintaining my weight as well. I'm 28 weeks and have only gained 11lbs. I'm measuring 2-3 weeks ahead, baby is in the 59th percentile, and his heartbeat is 150. Now to start going every 2 weeks!