In the making of Up, storyteller Pete Docter changed the main plot of the story multiple times - sometimes drastically, taking the story in a totally different direction. The original concept was of a castle floating in the sky, inhabited by a king and his two sons. His sons were opposites and couldn't stand each other - and they were vying to inherit the kingdom.
Then the story changed. Taking along only the title (Up) and a tall bird that had originally helped the brothers understand each other, Docter reimagined the film as the story of an old man, Carl Fredrickson, who eventually ends up with his eight-year-old stowaway, Russell, on a Soviet dirigible. Then that idea changed, and the Soviet subplot was done away with.
Eventually, Up became the beloved story it is today - a tale of a balloon house that flies to Paradise Falls. But only after many, many revisions.*
You see, the deal is, originality doesn't come from concept. Up wasn't born perfect - no story is. Every story starts out cheap. What separates the good stories - the original and affecting ones - from the cheesy stories is how often they are revised into a better work of art. Examine character motivations and plot twists - in making them better the story becomes less typical.
Everyone's heard that "great books are not written, but rewritten". But that great CONCEPTS are rewritten - that changes the way you think. If the plot and characters of a story aren't set in stone, if you're willing to completely change the story, then you can free your story from cliches - rewrite it into something that has never been done before.
Good revisions make originality, not good concepts.
And you know, that's encouraging. As bad as your story might be right now, it has the capability to become something great. Something original.
Don't give up hope, and don't give up tweaking. Both will see you and your story through.
* (All information regarding the development of Up sourced from Creativity, Inc. by Ed Catmull. Which, by the way, is an excellent read, and one I recommend.)