Size Matters?

I went for my 37 week visit today. I'm measuring small. The other midwife I have been meeting with hasn't seemed to concerned about my size and says I'm a small framed girl and I won't be carrying a monster baby belly on me. But I met the other midwife today and she seemed pretty concerned... concerned enough to ask for me to get an ultrasound done today. Unfortunately for me, my visit ran late because the woman who checked me in had made a mistake and forgotten about me. If I had been called in on time the tech would have still be available, but she had already left by the time they got to me. I'm slightly worried, but slightly not. I don't know. I mean, she moves like crazy and is strong as hell. An endangered baby wouldn't be as active as mine is. My weight gain has been steady and on point, her heart beat has been strong and great, my blood pressure has been incredible, I'm really young, active, and healthy. I should have no reason to worry, but now there is still that little concerned cloud of what-ifs in my head. I guess I'll see what they say after the ultrasound. Until then, I'll try not to worry :-/