Here's my response every time someone tells me some idea I'm writing with has been done already or how the story should go to avoid pitfalls other writers have blithely stumbled into, or when they tell me that a fictional creature is defined a certain way:

Alice: From the moment I fell down that rabbit hole I've been told what I must do and who I must be. I've been shrunk, stretched, scratched, and stuffed into a teapot. I've been accused of being Alice and of not being Alice but this is my dream. I'll decide where it goes from here.

Bayard: If you diverge from the path...

Alice: I make the path!

No two people tell a story in precisely the same way even if they witness it. Ask any lawyer or think about all the movies covering the same events or all the adaptations of the same story. 

"That the powerful play goes on, and you may contribute a verse." Walt Whitman

So tell the story you need to tell and don't worry about what anyone else is doing. If the story works for you and you enjoy it, you've already won. And love is contagious. If you love it, really love it, chances are someone else will too, even if there are a million other stories out there about dragons or vampires or love or death or war or pain or magic. 

(Serendipity) Dean: You know the Greeks didn't write obituaries. They only asked one question after a man died:  

Image credit: Martijnvreugde