I heard back from that agent again (fast, I know!) and she said that while I'd done a great job with the re-write, she still wasn't feeling it. She thought the opening scene a little generic (eeep! Don't tell me that. Do you know how many different opening scenes I've written for this book?) and she thought maybe it was more about taste, as in, she doesn't love it but its not to say someone else won't.
What I should do now is continue on with editing and re-writing until the manuscript is finished. But my problem? Often I get to this point and want to give up in favour of starting something new. But I really should stick with it. I've queried one whole agent with it (only because I wasn't quite finished yet and the opportunity was there) so if I actually got back to where I started with my plan and in a few weeks or months start an actual query process with all the agents on my list, I might actually get somewhere.
But to give myself a small break so my brain doesn't explode or I don't get totally sick of it, I might think about a different project for a few days, just for the fun of it. After all, I have to remember I'm doing this because I love writing.