Rejections absolutely suck, and I think it's awesome that you didn't have an emotional breakdown after receiving the first!
When I started this querying process in August, I was operating on the naive assumption that MY BOOK IS SO GREAT, THEY'RE GOING TO LOVE IT! I sent out queries in biweekly batches of 5 or fewer, and the rejections started to trickle in mid-October. So far I've received 10 rejections, and to be perfectly honest, I cried when I received the first one. Here are a few of the highlights: "I did not connect with the submitted material enough", "I'm just not drawn strongly enough to the concept of your story", "your work just didn’t resonate in the right way", "I'm not seeking to add material in that vein to my list", "the first chapter just didn’t pull me in as much as I had hoped" and "I don’t believe I’m the right person to represent it effectively".
The rejections were hard on my ego, but eventually my rational brain took over - someone who doesn't feel passionate about my work is NOT the right person to represent it! On the bright side, there were a few positive comments thrown into the rejection mix, e.g.: "I think you have an intriguing concept" and "there is much to admire in your work". I'm REALLY hoping these aren't standard form letter inclusions, so please don't burst my bubble if you know otherwise!
At the end of October, I received my first full request, followed by my first partial request 3 days later. Now I wait. Agonize. Hope.
Best of luck to you, I sincerely hope you receive some good news soon!