Mistaken for a vision, something of my own creation
I wake up alone, with only daylight between us
The “fiction” when “we’re not together” was something of the singer’s “own creation”. The singer feels that his imagination of his relationship, possibly continuing even after a breakup, is real, so real that he mistakes it for an actual “vision”.
In the third line, it becomes clear that he’s only dreaming. He wakes up from his dream to find himself alone. Most people only dream at night, hence, he’s separated from his lover by daylight, and can only be with her, in a dream, when night comes.
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