'unhappy day' is correct and usable in written English.
You can use it to describe a day in which something unfortunate happened, or a generally unpleasant day. For example: "Yesterday was an unhappy day, not only did I lose my wallet, but I also locked my keys inside my car."
So the brothers seethe, the wives snipe, and Tony drinks, as grievances old and new are aired in the course of an unhappy day that only gets unhappier as Tony's cut-rate plans for the funeral go absurdly awry.
"It was an unhappy day all around".
"I had lived 30 years without an unhappy day.
How the care from one wonderful youth or community worker can inspire you to keep going, be the light in a dark week, the joy in an unhappy day and an invaluable source of strength.
Instead we lay there on his bed, sad and defeated, him paging halfheartedly through the Murakami novel I'd just finished and me hiding in his copy of John Banville's The Sea, which, with its droll asides and descriptions like poetry, helped me keep my wits on that unhappy day.
They did, and then marched to Lake Carnegie and threw them in, for good measure.... Then my father, saying that it had been a "cold, unhappy day," went into Jadwin Gym to get warm with his classmates while I walked out on the field.
Happy Mondays' Bez has had an unhappy Thursday.
It was granted on the decidedly unhappy Monday, March 31.
As the banking system eats itself and every trading week begins with an unhappy Monday, most working pop musicians look on the headlines with a mixture of ennui and schadenfreude.
So, board members and other residents at the building were unhappy Friday when they received word from the city and the developer of the yet-to-be completed tower next door, known as One57, that they would have to leave their homes once again next weekend while the crane atop the tower was repaired.
(See: "Unhappy Monday For Wall St. ").
