A situation or action that is totally stupid, out of control; should not have been done in the first place.
Situation I walked into class when my pants fell down; man that's spiraling.
Action Writing a 10 page response for a one page response question; man you're spiraling.
A simplified way to describe a fast-declining mental/emotional state, often leading to short-term bouts of depression or anxiety.
"Hey, how's your day going?"
"Terrible. I've got three exams, two papers, and I can't find my keys. I'm spiraling, man."
"Hey, are you coming to the meeting tonight?"
"Oh, ok, feel better."