Feeling a bit discouraged

We met with the seller on Saturday. The kids were so excited. They couldn't wait to see which rooms were going to be their's. The realtor talked to us about a few things and then went back and talked to the seller.  Things were not as they seemed. As soon as we got there the seller started asking for more, we agreed to everything and even signed the papers but she wasn't confident enough to sign herself. She needed another day before she could give us a final answer. Well its been a week now and the seller has backed out. I am so disappointed.We have made plans with the hospital to bring our daughter home to this house under the impretion that the seller agreed to our offer. She even gave us permission to have the medical equipment company come to the house to inspect. Now she has changed her mind. We were up front with this women from the very beginning. We expressed to her how important it was for us to move forward promptly so we could get our daughter home. She should be ashamed of herself. I'm not sure what we are going to do at this time. Please keep us in your prayers