As so many have said, 3 weeks is WAY too early to know or worry about this.
I've read (and am still hoping!) that some people lose weight after they finish breastfeeding. I say that because I never lost the weight, even though I was exercising and cut out all the junk food. I was still easily 10 lbs over my pp weight. I couldn't wear most of my pp clothes because both my boobs and my waistline were much bigger than pp, although I was able to buy some clothes 1 size bigger that worked well for me.
But I was still nursing when I got pregnant again, so I never had a chance to find out if I would have lost the weight otherwise.
It's driving me nuts. It's driving DH nuts. But I'm trying to be patient. (DD will be 20 months old this week, so I've been patient, I really have been.)
But at just 3 weeks? Just try to get some sleep!
Jo
DD#1 "JellyBean" 6/08
DD#2 "Ha" 6/10
"Theory is great, but as I'm in the trenches of diapers and dishes and ear infections, I try to relax and focus on what's most important: love."--mjs64