Reflux and bottles

My 11-week old DD has silent reflux. She doesn’t vomit but she screams after feeds and had some weight gain issues. I usually breastfeed her throughout the day and DH gives her a bottle of breastmilk before she goes to bed. She doesn’t fuss on the breast but she does fuss at the bottle. When the doctor started her on Prilosec she had a great few bottle feeds where she took in 5-6 ounces! Now she’s maybe getting 3 and it’s a struggle. In addition to the Prilosec the doctor recommended switching up to a medium flow nipple so she can get a lot of milk as quickly as possible since I have a good letdown. Here’s the problem. I’m going back to work in one week and she’s going to need to get used to bottle feeding. And I don’t know what to do to help her. She’s been taking the same brand of bottle (Lansinoh) her whole life and only started having issues the last few weeks. I really think her fussing has to do with her reflux (as opposed to preferring breast) but I don’t know what to do to help her with the bottle and I have limited time to figure it out. Any thoughts?