The phrase "putting on cloud nine" is often associated with feeling ecstatic or elated. However, there are several antonyms that can be used to describe the opposite emotions. Some of these antonyms include feeling depressed, unhappy, sad, down, or miserable. When someone is feeling "put on cloud nine," they may also be described as feeling jubilant, exhilarated, overjoyed, or thrilled. Conversely, someone feeling the opposite might be described as feeling disheartened, despondent, gloomy, or melancholy. It is important to consider the context and perspective of individuals and situations when using these antonyms to accurately convey the corresponding emotions.