A small bunny in dire need of me

A few weeks ago our cat Autumn caught a small bunny and was playing with it. I thought it was stunned or in shock since it was shaking some. I picked it up hoping that I would be able to nurse it back to health and release it in a few days. It stayed in a cage with water and I gave her a little carrot. That night I watched tv and held her all the while petting her to see if she would respond. A few times she became more lively and I thought she was doing better. It made me happy. I prayed that she would make it since it was just little. I guess it was too much for her since she was still in the morning. I was sad and berried her next to our hampster in the side yard.