I've done things I've never seen anyone else do, yet I bet someone somewhere else has done something like it before. HDR, Draganism and another whose name escapes me are similar in look to some things I did a while ago and before these techniques became known or were even invented. My shots are done in a different way, one was even done using film. But it will always be assumed I'm copying others. I get asked about my HDR images, yet I've never done HDR.
I've got notebooks of ideas and sketches for things to do, some I've then seen in the Tate Modern and done 50 years ago. It's impossible to see all art/photography, so it's impossible to know if you are being genuinely creative or ploughing a furrow that others have been down before. Now with the web, it's even worse as you could be innovative and creative in your own country, now you have to be innovative and creative in the entire world. And as soon as you done something new and interesting, everyone is asking about which filter or plugin do I need to copy this 'unique' style.
Not to say that people don't or shouldn't use other work as a starting point. There is a tongue in cheek phrase relating to such things. Good photographers/writers/designers borrow, Grreat photographers/writers/designers steal.