How much weight have you gained?

Anne
I was about 140 before pregnancy, and now at 16 wks I'm about 148 lbs (I'm 5'9" so was on the low side of normal BMI pre-pregnancy). 
I've always known how much to eat to maintain my weight, and now I'm not eating that much more at all but I'm gaining steadily. That's a good thing, I know, but it still weirds me out! lol. Dr hasn't said anything, so I assume I'm not gaining too much but there's definitely some extra around my thighs as well. 
How much weight have you gained so far? Is 8lbs normal at 16 weeks?