Oh man, I can't imagine how icky that feeling must be!!
The encouragement I've been getting here for judging your own work applies to us both, I think, (and all writers really). But also the idea that the quality of your writing (one of the only things you can actually control) is only a small equation in the factor of landing an agent. There's so much luck involved. But the other thing you can control is how much you keep putting yourself out there and that sounds like the really hard part. But it only takes one lucky day to start the ball rolling!
The early positive responses like Pitch Madness reinforced that I was on the right track, though. But what I wasn't thinking about when I posted last night is that it's probably not the opening, it's the overall concept. I didn't realize this was going to be such a hard sell.
Ugh, I don't know if I should keep querying or not.