Baby allergic to protein in breast milk

So, a bit of my back story...

This is my 5th baby and I fought hard to breastfeed every single one. I have pcos and don’t produce much milk for very long. I also have had other complications like mastitis and complications during birth etc. well, this time I have fought hard again to be able to nurse. Especially with this being our last baby. We needed clomid for conception, I had cervical cancer removed the month before we finally conceived her, I had a very high risk pregnancy, and developed Hellp syndrome at the end. I had mastitis at the beginning with her as well. I continued to pump on the infected side and nurse on the other side. My nipples were so bloody and cracked, I was missing skin. I found out I’m allergic to lanolin(that made it even worse). And I bled during pumping on the infected side. I finally got over the infection with antibiotics and pumping non stop. I developed another massively clogged duct on that same side! Nothing was helping. Every time I would latch her the clog got worse and worse. So I continued to latch her on the other side. I was making enough milk to be able to feed her for over half of her feeding! This is such a big deal for me! Well, as time wore on we learned that she has a protein sensitivity along with a lactose intolerance and reflux. The more I nurse, the worse her tummy gets. After speaking with the pediatrician yesterday, he agreed that it was time to stop nursing and keep her strictly on the Alimentum. I’m miserable. I’m so bummed and upset about all of this. He says I can pump and store it bc babies almost always grow out of it. But, it has to be in a deep freezer and we don’t have one. Has anyone gone through something similar? Anyone have any advice? I was so proud of how far we’d come on our nursing journey and now this ironic dilemma is killing me. I’d love to hear stories and suggestions ladies please!