Omg i'm so sorry it happens to you... this is my absolute worst fear
Like when i have an idea i show it to the world as fast as possible so someone doesn't do the idea before me. I even get very scared of my ocs copying other characters it's terrible
But if you want reassurance, we all make our own versions of already made stories it's totally ok!! Like sci-fi or fantasy movies kinda all inspired eachother, with every new generation we get our own references that's the whole point in art industry!!
There's so many of us and only few get popular... but just know you're never ever alone and it should absolutely not discourage you to do your ideas really! You'll find your little community as every artist does