I feel depressed

I wrote a fanfic which I put on fanfiction.net - just a totally unrealistic yet fun story based on the characters of Pride and Prejudice. Well, apparently someone else on another website has written a story which is eerily similar to this one (they couldn't have copied me because they published it before me) and I'm being accused of copying by a reader. It's really depressing. If any of you write, you would understand how embarrassing it is, because the idea of copying someone else's writing is totally disgusting to anyone who writes seriously - as far as I'm concerned. I'm way too proud to do anything of the sort. I've said several times now, very strongly, that I didn't do it, but the girl says she's going to 'report me' to the person who wrote the other story. Although I don't really see what she could do (other than maybe get me banned from fanfiction.net?), it's really getting me down, and I feel really embarrassed, even though I didn't do anything wrong.