The significance of shells

With each minor disappointment
I harden a little
until one day I look in the mirror
and see a shell.
Tiny speckled swirl
steadfast but brittle
self-sufficient
neat
closed.
I curl up on the mantelpiece
with the photo frames.
Dwarfed by you
my children
and a carriage clock,
I'm unsurprised
to be overlooked.