For some, smoking is a form of self-medication to help deal with feelings of loneliness, sadness, and depression.
When someone quits, they are removing a major crutch for coping through the day, and it’s not uncommon to experience feelings of sadness or depression. In most cases, this should pass within a few weeks. Sometimes just talking with a friend can help, but if the feelings of sadness, anxiety or depression continue, talk to a doctor or pharmacist.