You have to eat normally instead of cutting down on food intake because you need the energy and nutritions to bf. Just try to limit food intake after 8pm but have all 3 normal meals and drink more water too. Can also have lesser carbs in your meals.
I ate like a cow when I’m breastfeeding, took me around 6 months to shed off all the extra weight and more.
During this period, try not to try on your old clothings (I know it’s hard and I’ve been there too! Also, stress contributes to weight gain for individuals and affects supply). Focus on eating and resting well.
You can try exercising to double up the process.