Military Science Fiction. Short Story found in an anthology. Mid 1990s. Paperback
Title was: _last_name_'s War
The last name was complicated to read/pronounce maybe Polish or Norwegian.
An American, an older man, say 40 years old (relative to a draft age of 18 years old) is drafted and fights in a bitter futuristic war where America is losing against an unspecified but superior enemy force. He has trouble with his memory, just vivid sequences then blankness between them. The war drags on for years. Women fight in segregated, all female units. There are cybernetic prostheses which can replace wounded limbs. There are combat drones and other robots.
Twist at the end is that it was all an artificially constructed reality in the character's mind, a government experiment to see if the average American still had the will to fight, even against overwhelming odds. Only a few weeks have passed in real time. Character is paid and given an honorable discharge and driven home to his normal life.