Switching to bottle feeding my LO breast milk

We decided to start giving LO bottles of breast milk but I pump 30 minutes every 1.5 hours and I typically only get around 1oz from each side. Is that normal? LO is 3 weeks old. We gave him some formula and he eats about 2oz each feeding every 1-3 hours. I’m not sure what’s considered normal 🤷🏽‍♀️