Depression is a disorder that manifests through excessive sadness, loss of interest in enjoyable things, and low motivation. It is normal to feel sad about major events, loss, and disappointment. In the case of depression, it lasts for at least weeks and affects your daily activities. Here are some ways to deal with depression:

A. Cognitive-behavioral therapy

B. Behavioral strategy

C. Cognitive strategy

D. Medication

E. Electroconvulsive therapy

Source: https://thiswayup.org.au/how-do-you-feel/sad/