Issues with supply

My baby girl is 16 days old. She had weight gain issues when she came home from the hospital when we were exclusively breastfeeding. Our pediatrician put us on a feeding schedule that included formula supplements. So, we would attempt to breast feed then give a bottle of formula. I also started pumping so that we could also measure how much breast milk she was getting. She is now gaining weight like a champ! However, she's still a lazy eater at the breast. Falls asleep after 5-10 minutes and has to use a shield to latch. Well, my supply is dwindling. I was getting 2-3 oz in a combined pump. Now I do good to get 1.5 oz! I don't even leak that often. Before I would leak anytime she cried. I'm already taking fenugreek and I made lactation cookies and have been eating those. What else can I do to boost my supply without hurting baby's weight gain?