"bitterly unhappy" is a correct and usable phrase in written English.
It can be used to describe intense feelings of sadness, disappointment, or despair. It is often used to emphasize the severity or intensity of the unhappiness being experienced. Example: Despite her successful career and loving family, Sarah felt bitterly unhappy after her divorce.
There, and later at Winchester College, he was bitterly unhappy.
Jean-François, she says, became bitterly unhappy once she became famous.
The house flourished but the marriage was bitterly unhappy and ended in divorce.
But once there she became bitterly unhappy and resisted many of the Shakers' practices, along with their religious teachings.
Prosecutors have painted Sergeant Bales as someone who felt "inadequate as a soldier and a man": drowning in debt, behind on his home payments, bitterly unhappy with his family and frustrated with a stalled military career.
City's Nigel de Jong put in a commanding performance, though Mancini also singled out Carlos Tevez – who he said might have contributed more had City not been denied the services of Mario Balotelli, whose three-game ban is one Mancini is bitterly unhappy about.
They divorced bitterly after five unhappy years of marriage.
"I'm not unhappy enough," Mr. Houben bitterly replies.
Boston-born Moshfegh is longlisted for her 1960s-set novel which tells the story of an unhappy young woman and a bitterly cold Massachusetts winter.
He shares, too, an unhappy relationship with his family: Charlie digs bitterly, from time to time, at "my father's cupidity and chronic envy, my mother's febrile regret at having married an impossible cad" and at his brother's "crawling disgust at anyone and everything.
On the one hand, the famously unhappy union between Dickens and Catherine Hogarth — who was cast off bitterly by her husband after she bore 10 children and experienced several miscarriages, all in a period of 15 years — makes him think of his own parents' marriage.
