Tailspin

Noun

 * 1) The rapid, uncontrollable descent of an aircraft in a steep spiral.
 * The loss of the third engine threw the plane into a tailspin.
 * 1) A severe mental or emotional collapse; emotional breakdown.
 * Just hours after leaving the institution, she suffered another tailspin.
 * 1) Any sharp, sustained, often uncontrollable descent or decline.