Do you remember the last time I saw you?
It was spring and the light purple cherry blossoms fell like soft snow does in the winter.
And every once a blossom fell, it made a little shadow, and without a sound it landed on the ground, harmless, quiet and soothing. 
You could hear the river rush and the birds sing.
There were no clouds in the sky and the sun was shining, really
It seemed like the perfect day. 

but just when you looked from the third person view.
the view you see through your phone screen, as the cherry blossoms give in gravity and fall on earth. Peaceful.
A beautiful fassade. 5 meter thik walls and so high, that you couldn't see an end. 

In this girls mind, it was a storm, and not even trees were standing anymore. Her mind was an endless dessert, but instead of the golden sand that blew everywhere, there was something that looked like black tar lying on the ground. And there wasn't a sun. Everything was black.
Simply the moon, the only light in this darkness, was shining far above her. 
she wanted to reach it, wanted to the last light in herself to become bright again-
but wasn't able to move. This place was hell itself. Cage like, hell.

But meanwhile, the people walked by, the sun was still shining. cherry blossoms still fell softly, the wind still blew mildly, there were still birds chirping from far away. the sound, sinking in the crowd of humans walking and talking. 

No one new of this girl, dying more and more with every second. 

so, don't tell people they're ok, or that it can't be that bad. 
you have no Idea. Because you can't see the pain.