Lactose intolerance

My LO was born at 32 weeks she's been in the nicu for almost two months. I've been exclusively pumping and she's bottle fed but she's been having bloody stools. First they thought it was just the fortifier so they tried 2 different ones still bloody stool. So she was just on breast milk all week and she had another bloody stool yesterday. So now they think she has a milk protein allergy so I was told to eliminate all dairy from my diet. It's seems like it's going to be so hard to not have dairy products I eat dairy with almost every meal. Anybody else gone through this?