feeling guilty

I have breastfed my LO for 5.5 months and am slowing transitioning her to formula. She has a cows milk allergy so I have been without dairy the last 4.5 months. I can deal with not having dairy but if I slip up and ingest the smallest amount it make her stomach hurt so bad and I feel horrible. I feel like formula would be better so she doesn't hurt but I feel guilty because I can breastfeed and so many can't that want to. I also love the convienence of BFing but pumping while working is getting to me. I love the bond I have with her while BFing but I want my body back and I feel HORRIBLE. Anyone else do this and have advice??