The phrase "sinking feeling" is typically used to describe a sense of despair or hopelessness. Antonyms for this phrase may include terms such as "euphoria," "elevation," "elation," or "joy." These words connote feelings of happiness, excitement, and enthusiasm, and are often used to describe moments of positivity or success. Other antonyms for the phrase "sinking feeling" might include terms like "confidence," "optimism," "hope," or "faith." These words suggest a sense of trust and conviction in oneself, one's abilities, and one's future potential. Together, these antonyms offer a broad range of positive emotions and ideas that can counteract or mitigate the negative connotations of the phrase "sinking feeling.