Hiya Plas - hows the baby doing now? I think six weeks is so young that she may not have finished weaning yet, which is why you may have found it difficult to place food in front of her and get her eating it.
Let's hope that with the good advice from others, and with your own loving care, she is now doing much better. I guess you will have tried CimiCat from the vet or something similar from a good pet store?
Good wishes and hope both kittens are doing well.
