Very sorry to hear she passed. It's like that sometimes with chicks...they make us all happy and excited one minute, then sad the next! Take solace in the fact that you did all you could for her and that while her life here may have been short...she was not shortchanged. For she had your love, and that counts for much!!!
make a seperate brooder inside the brooder ( just a small box with some water and feed, under the heat lamp) then try electrolytes in her water. ask a local bird vet for some more advice tell them the symptoms and maybe that will help.it will take some patience and a big ole dose of tender, love and care.