Go work in the food bank or help unfortunate children. Another urges me to be grateful for all my blessings. She is horrified at my condition. You don't have cancer or some terminal disease. Visit the hospital.
People there have a right to be depressed.
Many people suggest books. Some are religious. Some are self-help books. Some offer profound interpretations of life. Some suggest ways to change outlook or behavior in order to ensure a calm and cheerful mode of life.