My old childhood friend Fiamma has recently moved back east after studying chinese medicine in San Diego and I am happy about it. She had some interesting stuff to say about my strange illness:

In Chinese Medicine, simultaneous vomiting & diarrhea is called "sudden turmoil disorder." Seems appropriate. Without knowing more about the "event" and your medical history etc, it seems like the 2 main possibilities are some a)sort of buggish culprit (the source of which can be difficult to determine, being that there are so many things we put in our mouths over the course of an "incubation period," which can be 2-3 days); and b) an irritable bowel type condition. Although a) can't really be ruled out, the fact that this has happened before suggests b). I don't know how much you know about IBS (s=syndrome), but the good thing is that there's no really horrible things going physically wrong with your parts, because it's a "functional" problem rather than "organic." Although the causes are speculative, it seems to me that it indicates a more sensitive nervous system, and various triggers can overstimulate it & cause it to go haywire. Hormones are directly involved in stumulating the nervous system (which controls your bowels & everything else), stress hormones in particular. That is why stress can be a trigger for an IBS "event." It doesn't mean that the condition is psychological, by
the way. The hormones & chemical changes are very real. So is the shit & vomit! (Other triggers include certain foods that are too difficult to digest & irritate the bowels). But Irritable Bowel Disease involves intestinal pathological changes that are more of a concern than IBS b/c the degenerative changes can oviously get worse. You do have the option of getting yourself checked out again to rule out those pathological changes (especially if your last test was inconclusive). At that point, assuming they don't find anything, IBS would be a likely diagnosis. Especially if you tend to have minor GI unpleasantness semi-regularly (tummy aches or something of that nature). These things tend to be congenital.

me again: I've thought for a long time that I have a mild case of IBS, and from what I've read online I don't have IBD (which is much nastier). I'd much rather have something cureable so I can be rid of it. Sigh. I did call my doc finally; I'm waiting for him to call me back, if he ever does.