I am almost 10 weeks, and even though I have been eating a LOT more food, and fatty foods like chicken pot pie, because I feel starving, I don't seem to be putting on as much weight as I thought I would (for what I've been eating!). In fact, certain parts of my body seem leaner (my face seems thinner, my arms seem thinner). I actually think that making a baby is burning a lot of calories for me, and increasing my metabolism perhaps? I feel like a growing teenage boy that is a bottomless pit, and you don't know where they are "putting it."
My tummy seems more bloated, but I think it's constipation and the womb increasing in size. I haven't weighed myself though, and I've probably gained weight from my boobs being larger and the tummy sticking out. But when I wear a baggy shirt, I swear the rest of me looks more slender, like I took up running or something. So I could see that if my tummy wasn't slightly protruding and my boobs weren't a lot bigger, maybe I would have "lost" weight in other areas.
Have you heard of this weird fad diet called the "hcg diet"? I'm not sure how it's supposed to work, but people inject themselves with hcg (the pregnancy hormone) because they say it makes them loose weight. I have been looking at my arms and face, and even my ribcage/back area seems leaner, and thinking to myself that I am on the hcg diet, because I think certain parts of me are thinning out! :) So ya never know. Maybe your metabolism has gone up. Just my thoughts.