Help!!!!!

So I'm breast feeding and I wanna lose 50 lbs. I haven't lost anything since I had my daughter almost 3 months ago. I been staying the same. I thought I would lose weight because I'm breastfeeding cuz I remember with my son I only breastfed for 3 weeks and I lost weight in those few weeks. Also I'm afraid to start eating portion control due to not getting enough calories while breastfeeding it's really holding me back. Got any ideas. I know how to lose weight I lost weight before I just never done it while breastfeeding.