Postpartum Depression

A 28-year-old single mother of a 3-month-old son reports severe fatigue, general loss of interest, irritability, poor concentration, insomnia, low energy, and tearfulness that have lasted for 2 months. She had similar symptoms for several weeks when she was 18 years of age and again in mid-pregnancy, but her symptoms resolved spontaneously on those occasions. She is not suicidal or psychotic but feels that she cannot cope. What would you advise?