Whistling in the dark 

To comfort yourself via distraction when you cannot avoid a frightening situation.

While her mother was in surgery, Norma tried to remember all the state capitals. It was her way of whistling in the dark.

Whistling in the dark by NH Baritone January 9, 2008

Whistling in the dark 

To fear the worst and hope for the best.

"The mayor'll call...he's got to!"
"You're just whistling in the dark, Larry The Baby Killer."

Whistling in the dark by Macsotsu March 2, 2005