The book betrayed me. Knowledge is power, it seems... like shaking up a pop can.
As has been confirmed both by my internet beer friend and the lady at The Cork and Cap here in Jackson, the first couple of days in the fermenter require a different kind of airlock. You run a rubber tube into a glass of water and let the gases bubble out into that. Apparently, that handles the pressure better than the "bubbler" airlock I had on there.
The book describes these two pieces in unmistakably interchangeable terms, which I double-checked last night to make sure. I thought I would be cool with the bubbler, and then I got bubbled.
In addition, it turns out that the beer probably wasn't spoiled after all. The positive pressure from the gases coming off the yeast, in addition to the hostile environment for invading bacteria, probably prevented any contamination of the beer itself, and I could have saved it.
More guilt! Shame! Why did I pour that beer down the drain?
All right, so I'm reading up some more, and I'm trying to decide what I'm going to do next. I can't start another batch this weekend, because I've got a lot going on. In the meantime, I think, I'm going to come up with a beer to try next. Maybe I'll stick with the brown ale, maybe not. I dunno yet. If you have any suggestions, feel free to comment. Thanks!