The quest for publication is hard. As with everything in life there are soaring highs and gut-wrenching lows. Kind of like a roller coaster. You paid to get in, you waited in line, and once you're on the ride, you're exhilaration and terrified. You're screaming and laughing and holding your breath.
So here's my advice, writers. The lows come after the highs, and the highs come after the lows. When you're down, always look up. When you're up, never look down.
But always, always, always keep riding.