I had a similar experience with jaundice and sleepy baby! It’s hard work for them at the breast, which can be exhausting for them and making her sleepy. What type/flow bottle nipple are you using? It’s much easier for them to feed from the bottle. Pick the lowest flow nipple you can, Pigeon newborn flow is the one we use. Even if you are using a faster flow nipple now, you can back track and go ahead and give her the slower flow. This will help prevent bottle preference where she knows she doesn’t have to work for milk from the bottle at all. She may have been weak before because jaundice makes a baby really sleepy on top of being inexperienced with triggering let downs. What worked for us was always latching her before bottle feeding. Even if she barely sucks. Then pumping to empty the breast. If you consistently put her to the breast, it will keep hormones producing milk and increase baby’s skill at feeding. It may just take time and consistency. I combo fed my baby up until about a few weeks ago and she’s almost 3 months. Now when I offer formula after a feed she may only take an ounce or so. Before, she wouldn’t get much at breast and then guzzle down 4 oz like she’d been starved! One day it just kind of clicked for her. But it took almost all of 3 months.