Welcome!
Congrats on your weight loss so far and an even bigger congrats on your new baby!!! I think it's awesome that you are making breastfeeding a priority! I know it's a lot of work in the beginning, but it's such an amazing thing! I am not currently breastfeeding, but I breastfed both of my children, my youngest self-weaned about a year ago, right around her first birthday. I truly miss nursing her!
I had success losing while nursing w/o compromising my supply by following the paleo nutrition plan/lifestyle & getting in workouts about 2x a week. Nursing actually eased me into paleo because I had to cut out dairy anyway because my daughter is allergic to it.
If you are looking for something to drink besides water, I reccomend mother's milk tea, it's good for your supply! I liked yogi brand & traditional medicinals and I usually drank it iced!