1. Physiological factors: Emotional fluctuations and feelings of unhappiness may be caused by physiological reasons such as hormonal changes, lack of sleep, or physical discomfort.
2. Psychological pressure: Recently, one may face pressure in their studies, work, or interpersonal relationships, which accumulate unconsciously and make them feel tired and unhappy.
3. Environmental impact: Changes in the surrounding environment, such as depression caused by seasonal changes, monotonous living environment, or reduced social activities, may affect mood and make people feel unhappy inexplicably.