Okay, I'm panicking slightly. I was just scrolling through the latest stories when I came across a Marauder fanfic and decided to read it.
And now I'm in shock.
It's not word-for-word what I've written, but the first chapter starts off with Mr Potter telling James that he mustn't turn students into a tadpole, just like mine does. At first, I thought it was a coincidence, but as I read on, I realised that a lot of aspects are the same as my story. James meets Sirius when Sirius asks if there's any room in a compartment, then the two boys talk for a bit, just like in my fanfic. They leave the compartment and meet a prefect who Sirius flirts with, and the boys spot Peter Pettigrew, who is being bullied. And Remus and Lily intervene, just like they do in my fanfic. Later on, in chapter two, Sirius receives a howler from his parents and James makes a joke about adopting him, just like in my fanfic.
Am I just being paranoid?? It's not like the author has copy-and-pasted my fanfiction into theirs. They've just copied details. Quite large details, but still. What do I do?