I gained 30-40 pounds both times I breastfed my daughters (10-12mo each). Truly, if you just stay reasonable so that you aren't gaining a ton of weight, you'll be in the habit of doing the right things, and it will come off when you've finished breastfeeding. It's no joke that your body does strange things during pregnancy and breastfeeding! Especially at 6 weeks pp, at least give your body some time to readjust.
I'm just now getting off all that pregnancy and breastfeeding weight, and it's 8 years later! You're ahead of the game if you can hold the line in a healthy way.
Start Weight 240 on June 25th, 2012
Current Weight 211 on October 21, 2012
Goal Weight 180 by Summer 2013