A phrase used on the end of sentences to enchance the previous statement's value.
'to the days' has a similar function to the adjective-enhancing 'very', although comes after the adjective instead of before.
'to the days' implies a strong tone with it's increased emphasis.
I only got 3 hours sleep. I'm 'very' fucking tired.
This statement becomes:
I only got 3 hours sleep. I'm fucking tired 'to the days'.