So anyone have to have gone on a dairy free diet?

My boy has a protien allergy. A lot of explanation to why he was loosing weight under the 9th percentile still 3 weeks later... and not taking well to breast milk and kept being hungry from it. On top of a serious reflux problem😭

We are being given prescription formula at the moment as he was taking more to formula. (Still hungry from it and having problems)

But any of you ladies have to have done this diet. How do I do it? I want to breastfeed completely. But my diet is very dairy based and I know it's seeming difficult to do right now.

Looking for some advice, and any foods that are best in this situation. Please be kind about it, all a bit upsetting that my poor boy is having so many issues😩🥰