The phrase "getting second wind" implies a sense of renewal, vigor, and energy. Its antonyms, therefore, would depict the opposite: fatigue, exhaustion, weariness, and lethargy. Some possible phrases that could convey these antonyms may include "running out of steam," "feeling drained," or "losing steam." Whereas "getting second wind" usually refers to a resurgence of energy to continue with a task, its antonyms usually imply struggling to keep up, losing interest or motivation, or acknowledging one's limitations. In any case, whether we "get second wind" or not, it is essential to take the time we need to rest and recharge when necessary.