In short scifi film Sundays by Mischa Rozema, Ben imagines the end of the world to be a terrifying nightmare. An unrealized recollection of a previous existence.
Ben realises how much he needs Isabelle, the one and only love of his life, as he begins to reflect on his past with her. This is the beginning of an existential spiral into doubt and a frantic search for answers.
The scenario shown in this reality is shocking, unexpected, and bleak. This is obviously not his world.