Loss of appetite in pregnant sows

I have a sow in its second month of pregnancy who ate well the 60 first days, but now everything changes, and it doesn´t want to eat anything,and when it drinks water then it vomits with a yellow colour and with a strong smell. We gave it antibiotics to stop the pain but we had no luck. We are desesperated since 8 days has passed by in the same situation. What do you think?