post-barnum depression 

n. Moderate to severe depression in a performer or staff person after giving birth to a fantastic blow-your-mind show, when the cast and crew diaspora leaves your hitherto fervent banner flaccid in the listless echoing breeze. Onset is typically a few days after the blowout closing party.

Symptoms include sadness, fatigue, insomnia, appetite changes, having the libido of an awkward teenaged virgin, crying episodes, hysterical laughter, irritability, staring at Google Maps, the tuneless humming of barn-revival spirituals, chromatic-motion melodies in 6/8 time, or minor-key adaptations of Survivor's 'Eye Of The Tiger', and Facebook status updates.

Food-related cravings are not uncommon, especially for hot dogs, or paper and plastic bags of salty-yet-sweet snack foods (e.g., kettle corn). A dull disappointment is inevitable when the lid is removed from a can of peanut brittle and the sufferer is not EVER greeted by spring-loaded snakes. Honestly, what's the use.

Commonly abbreviated as PBD.

Closely related to "post-camp depression" (PCD), "post-con syndrome" (PCS), "whoa, too fun" (WTF).

"Joseph has to come up with a usage example for urbandictionary.com today, but his post-barnum depression is pretty severe. He just keeps hanging upside-down from his workstation desk and calling his mouse Templeton."

post-barnum depression by Joseph of Windows to Sky August 12, 2009