The phrase "sick at heart" is often used to describe a deep feeling of sadness, distress, or melancholy. However, there are several antonyms for this phrase that can convey the opposite emotions. These antonyms include joyful, elated, jubilant, ecstatic, exultant, and euphoric. Joyful refers to a feeling of great happiness and delight. Elated means feeling overjoyed or proud. Jubilant conveys a sense of triumph or exultation. Ecstatic describes intense happiness, emotional excitement, or enthusiasm. Exultant suggests being extremely happy and triumphant. Euphoric refers to a feeling of intense happiness, elation, or pleasure. These antonyms can help to communicate a range of different emotions and moods.