To be unbelievably tired beyond belief. When youhave beenphysically and mentally drained that even the idea of sleep requires too much effort.
"I have had two exams today, then went to the park and played football for an hour and a half, then revised for two hours, and now I've only just got back from the gym"
term used to describe the situation of having too many things to do, too many people needing things from you, too many places to be, with more things popping up constantly, that you feel panicky and helpless and overwhelmed.