However, the meaning of dreams is not single. It may also reflect your deepest hopes or worries. For example, you may be worried about your girlfriend's health or safety, so she becomes a jade rabbit in your dream, which means you want her to be healthy and happy. Or, you may want your girlfriend to be more beautiful and kind, so she becomes the jade rabbit in your dream.
In a word, dreaming that your girlfriend becomes a jade rabbit is usually a positive dream, indicating your love and concern for her, or wishing her happiness. But I suggest you seek the help of a professional psychological counselor in order to explain the meaning of dreams more accurately.