Similar stuff has happened to me

Similar stuff has happened to me. The only thing you can realistically do is see if you can retweak certain plot points or elements into a new story. Either that or scoop up your already flashed-out characters and see how they fair in a different context. Sorry about your idea though - at least you’ve actually completed a project!

Came to post this same FML, but I guess someone beat me to it by a couple days.

I used to be in publishing. Trust me, submit the book. There are lots of books that have very similar plots. As an author, who is very close to your own material, that other book may look like it's almost your story, but your story is still your own. Stephen King wrote The Stand, and Robert R. McAmmon wrote Swan Song. They're almost the same exact plot. They're also both fun, enjoyable, worthwhile novels, and the world would be a little poorer without either of them. Romance novels all have the same three (some say five) plots, and they bring lots of pleasure to the readers. Write the story you want to tell, and share it with whoever will read it. And if a publisher doesn't want it, publish it yourself (get an editor though). There's no rule that only one person can ever tell a story ever. Your version may resonate with different (or the same!) people than someone else's. You aren't an author because you told the story first. You are an author because you write stories.

As the saying goes... all the original ideas have been taken. Maybe rewrite it to take place in space!😂

No one cares about the plot. As long as your sex scenes are steamy and dirty, you’ll be creating great literature!

Absolutely submit it. the year Harry Potter came out there were several similar books.

Submit it for sure. Harry Potter does have a some amount in common with The Worst Witch and The Hunger Games is pretty much a rip off of Battle Royal. I'm sure you'll be ok.

You're not going to find an original plot. They've all been done. how you execute that plot is where your book will stand out. Best of luck with the submission, and if all else fails, you can self-publish.