She tried to be happy. Time and time again she would force a smile, and try and make the most out of her shit situation.
But I think, there comes a time in your life where all this effort drains you - you can't be happy anymore; you can't even try to be - and so, she shut herself away.
She became isolated.
She wouldn't speak,
unless spoken to.
She wouldn't fake a smile anymore - even that became too much hassle and effort.
She wasn't herself, yet nobody noticed.
Nobody notices anything.And that's why, it was so easy for her to slip away - and before, she lost herself.