This is an incredible write Elle - I have read it three times already and I will be reading it again! I felt all the emotions in this and I really got your metaphors right from the get go.
Some of the (many many) lines that really stood out for me are:
'There are no violins here, no crescendos, only an electric keyboard mimicking the tinkling quiet of a winter’s night.'
'He begs me to stay, pealing like a silver bell. But Christmas is a cold lie whose jingle rings hollow.'
'She is lumens, she is Lux, and as she crests the horizon, she is one with the Dawn.'
'It sent tendrils of sunlight and whispers of songs'
'Lux is suffused with gold and silver motes; phosphorescent.'
'I am Lux Lumina, boy. I am a Beacon of the Dawn and a daughter of the Sun. Come, let’s be poetry together.'
So much beauty and pain woven into this one - I love it!