The key differences between depression and a rough patch are duration, intensity, and functional impact. Temporary sadness usually has identifiable causes and improves within days or weeks. Depression typically lasts at least two weeks and includes multiple symptoms like persistent sadness, loss of interest, sleep changes, fatigue, difficulty concentrating, and feelings of worthlessness. Depression also significantly impacts your ability to work, maintain relationships, or care for yourself.
If you're unsure, a mental health professional can help assess your symptoms.