A good site to surf to on occasion is rejectioncollection.com. In fact, the site's founder, Catherine Wald, has written a book: 
When you're feeling down, go read about rejection. In fact, here's a tale from the website….
In 1996 I thought about giving up my dream of becoming a published author. I had written two novels, found a wonderful agent and, by her account, had the best rejection letters any writer could wish for.
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But despite them all… or to spite them all – I'm not sure which – I took to the web.
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About 16 months after my web site went live, in February of 1999, Lip Service – the little book that could – was discovered on line by an editor at the Doubleday Book Club who bought it as an alternate book club selection. It was the first time a major book club had bought a self-published novel. The first time a book had been discovered online.
Two weeks after that Pocket Books offered my agent a contract. At that point Lip Service became the first e-book to cross over to become a mainstream novel.Lip Service – the book no one wanted in 1996 – has now sold over 60,000 copies and has been published in England, Germany, Israel, The Netherlands, France and Australia. The trade paperback version has just gone into a second printing.
If you don't know by now, the author is M. J. Rose. 🙂 Good thing she didn't give up. And neither should you.