Write "the end" as many times as you like -- it doesn't necessarily mean that you're all done with your book. Many writers, in fact, spend more time editing and re-writing than they ever spend on creating that first draft. It's really easy to get caught up in perfecting a book, to go back to it again and again...and that makes it really hard to release your book so others can actually read it. How do you know when you're done, and when a book is really ready to be released? The answer is actually pretty simple.
When Enough is Enough
Some scenes just won't go away, even after you put them on the page. Some scenes demand to be re-written, perfected, over and over again. And it's easy to get caught up in that. Every writer wants to produce a perfect book. But at some point, you've got to stop typing, stop reading, and finally say done.
You're the only one who knows when you finally get to that point, and it changes with every single book. When are you done writing that tricky scene? When you finally stop thinking about it. Writers re-write scenes because they can't get them out of their heads; they keep playing, and re-playing inside the mind, and changes have to be made. When you finally get that out of your head, then you're finally done. When you're done re-thinking, second-guessing and re-working, then you're finally done. If it stops keeping you up at night, stops distracting you during the day, stops haunting you when you're supposed to be doing other things, then just stop. You're done messing with it.
When your head space is calm and quiet, it's because the work is finally done. It's because enough is finally enough. Don't go back to the book and look for more work. Trust yourself, and put it out there. You'll learn more by publishing than by proofreading for that seventh time.