2 month old refusing bottles and losing weight

My sweet girl was born at 31.3 and has been home for two months. The first month I was giving her pumped breastmilk and fortifying to 24kcal and she was crushing her bottles (on medium flow) and in the 95%. She was doing so well our dr said we could stop fortifying. Over the last month she has started to refuse feeds and cry when getting into the side lying position to eat. I started calculating how much she was eating and it is between 17-20 oz a day. She has lost weight and is at the 60% now. She lost an ounce from last week. I have tried four different bottles and faster flow on each bottle. She does not like the faster flow and cries when we try them. Feeds just take a really long time and I am not sure if something is wrong or not. Takes about ten min an oz. Does anyone have experience with their kids losing weight or not eating as much when you stopped fortifying? It makes sense her weight would slow but I don’t know if she should be losing weight like this. I keep bringing up to the drs that maybe it’s a bottle aversion but they don’t have much to say about that. Does anyone have experience with this?? via /r/NICUParents https://ift.tt/mpl4dyW