Best products to up my milk production

sa

Took my 5 mo daughter to the pediatrician and she’s losing weight. I’m breastfeeding. I don’t think I am making enough. I tried pumping to see how much she’s getting and was only able to get 3oz combined. I drink on average just over half a gallon of water per day (I have a water bottle that I use every day). I want to keep breastfeeding if I can.