belly shrinking/weight loss

And it's distributed differently, but I look at my "profile" in the mirror and it just seems like it's smaller. I am 33w2d and have an U/S tomorrow to see how little one is growing. I also have lost about 2-3 lbs as well. I know that the baby is supposed to gain 0.5 lb a week til delivery and that it's possible a mother would lose weight towards the end, but this just seems a bit early. I would call my doctor, but she always just tells me to go to L&D floor (she always makes me feel like I'm overreacting, but that's a whole other can of worms) 

UPDATE: U/S went well, fluid levels are good, baby is actually measuring 2.5 weeks ahead and already weighs 5lbs14oz! 😱