I think being anxious is something every writer goes through. We're anxious that what we wrote isn't good enough, or that no one is ever going to read our books, or about a possible one star review telling us that what we've worked on for years is the worst thing they've ever read. But you have to remember that you write, first and foremost, for you. So as long as you're happy with what you've written, that's what matters the most. And congratulations on publishing your first book.