Example : Felt regretful over his vanished youth.
Regretful over mistakes she had made.
He felt bad about breaking the vase.

Synonyms : bad, regretful

Example : My finances were in a deplorable state.
A lamentable decision.
Her clothes were in sad shape.
A sorry state of affairs.

Synonyms : deplorable, distressing, lamentable, pitiful, sad

Example : A sorry horse.
A sorry excuse.
A lazy no-count, good-for-nothing goldbrick.
The car was a no-good piece of junk.

Synonyms : good-for-naught, good-for-nothing, meritless, no-account, no-count, no-good

Example : A blue day.
The dark days of the war.
A week of rainy depressing weather.
A disconsolate winter landscape.
The first dismal dispiriting days of November.
A dark gloomy day.
Grim rainy weather.

Synonyms : blue, dark, dingy, disconsolate, dismal, drab, drear, dreary, gloomy, grim