Daughter 9 months + second pregnancy 13-14 weeks. How to stop a child…

Daughter 9 months + second pregnancy 13-14 weeks. How to stop a child from breastfeeding? There is a threat so we need to stop breastfeeding sooner ? The mixture doesn't drink at all, we can drink 2 sips and immediately starts diarrhea, vomiting and fever up to 40 degrees. We called an ambulance and were admitted to the hospital for 2 weeks. They took intravenous fluids, antibiotics and probiotics. 3 times in 1.5 months. At the beginning they thought maybe the mixture didn't like it, tried giving hypoallergenic too, the same thing repeats. The daughter left with mom and she even didn't drink water, she was crying all