Hear the Sound of the Milky Way Falling

Because he failed to confess to his best friend,
the male protagonist developed a 'post-traumatic stress disorder' due to his first love failure.
In order to be able to successfully fall in love in the future,
he can only regain the object of the confession to relieve the happiness,
but the best friend who has never thought of missing for eight years
is actually a god suffering from depression.