If I were to diagnose myself, what symptoms of depression would I look for first?

Criteria, seek help. If you are suspecting depression in yourself, seek assistance and an evaluation from your doctor. Major depressive episode consists of 4 of the following symptoms lasting greater than two weeks: depressed mood, changes in sleep, lower energy, poor concentration, changes in appetite, feelings of too much guilt, inability to enjoy, moving slower or too fast, racing thoughts, and suicidal thoughts.