Actions and feelings go together; by regulating the action, which is under the more direct control of the will, we can indirectly regulate the feeling,  
Thus, if your path to cheerfulness is lost, sit up cheerfully and act and speak as if you are cheerful. Try it. It works wonders! Put a big, broad, honest-smile on your face; throw back your shoulders; take a nice deep breath; and recite a few verses from the Holy Qur’an. Then recite a munaajaat or qasida to yourself for a few minutes. You will quickly discover that it is physically impossible to remain 
blue or depressed while you are acting out the symptoms of being radiantly happy! 
Research has shown that positive thinking and pretending to be happy can in reality lift up the moods of the sick. The divinity that shapes us is in ourselves: our thoughts.