Well, apparently something called a vasovagal syncope can cause you to temporarily pass out in response to a sudden decrease in blood pressure (which happened at 4am when I had a massive *ahem* ejection on the toilet seat).
Your body freaks out at the prospect of your brain losing blood flow, so it shuts down consciousness until you're lying flat on the floor in cold sweat with a nasty bruise on your chin where it hit the sink counter.
Not knowing this weird piece of human physiology, I drove myself to the most highly-rated emergency room in my vicinity to figure out what had happened (and also to replenish all of the fluids and foods I couldn't hold down).
I get a jolly, young emergency doctor, who explains the whole syncope episode and how it occurs more commonly that people think (imagine straining on the toilet seat, only to find yourself sprawled on the small, cold floor). I feel a little better, getting my blood test to eliminate liver or kidney dysfunctions, an EKG to cancel out heart problems, and an IV drip to replenish my fluids.
Equipped with prescriptions of Pepcid and Zofran, my stomach pain is now more accompanied by a peace of mind. And if that doesn't work, I distract myself from the pain by thinking of paying 10% coinsurance for this ER visit that is going to cost me.