At a loss of time. Usually happens when either dumb, drunk, high, well-sexed, post-comatose, or cerebrally traumatized. Usually leads to negativeconsequences...
I was boffing my secretary so hard that I became temporally disoriented and missed my 3 o'clock.
Me and Rob got spliffed and, in a classic example of temporal disorientation, forgot to meet up w/ my hook up for another bag.
Disoriented is the American English version of it's more clunky sounding British English counterpart: disorientated. They both mean to be confused, lost, or to have lost ones bearings or sense of direction.