We don't have scales, so I have no idea how much I weigh (ignorance is bliss!)

If you're worried though, ask your doctor/midwives if your weight gain is healthy.
And of course you've gotten fatter in other places, it's just that in proportion to your belly, you'll still look small! I reckon my bb's and butt are massive, but they look small still, cos of the belly And like others have said, all that other...stuff. Extra blood, fluid, icy poles (ahem). Just be healthy..for the most part..and check with your dr/midwife if you're really unsure.

And put the scales away!