On a streak means to be on a run of success or good luck. Some antonyms for this phrase could include, "in a rut," "struggling," or "losing streak." In a rut implies a feeling of being stuck or stagnant, while struggling suggests a lack of success or difficulty achieving one's goals. Similarly, a losing streak means a period of consecutive losses or setbacks. Conversely, synonyms for being on a streak could include, "in the zone," "flowing," or "on fire," all of which convey a sense of confidence, success, and good fortune. Antonyms and synonyms help to provide clarity and better understanding when describing a specific situation or experience.