My Little Pony: Friendship is Magic - Script Update

I think you guys are misunderstanding this, she's just saying she has mixed emotions about finishing the first draft of her episodes. She's not saying the series as a whole is is over.

Guys, guys, people write "the end" on the last page of a manuscript to indicate that the manuscript is over. She's talking about how she finished writing an important episode, which will of course have an ending. This doesn't actually mean that the series is over. Merely that she found the episode to be particularly exhilarating and that it will not be infinitely long.