Something terrible is happening in my stomach.
Actually, nothing is happening, and that seems to be the problem. After my long run yesterday, I took in a large amount of fluid, but not very much food. I did not realize this fact until late in the afternoon, and as a result, I found myself trying to make up for lost time. I got overfull pretty quickly, but with a bit of moving around, I got back to a level of comfort.
Today, I was not so lucky. We had a nice group run this morning, and after rehydrating, I had a little coffee. Before long, I was off to rehearsal where I would eat more bagels than I care to admit and continue throwing down coffee. By the end of four hours, I was feeling great about my character and terrible about my bodily comfort. The fresh air of the walk to the bus helped, but I decided at some point that what I really needed was to get something to eat.
As it happened, I still had pizza in the fridge, so I came home and took care of that. Then there were hot dogs. Then more water. And milk. And water. I was hungry and thirsty, and nothing could seem to quench either. That is, until I had gone too far. I'm now quite uncomfortable.
Very often, you don't see the trouble coming until you're already over the threshold. It's the reason injuries in running are so prevalent. In my case, injuries don't actually happen while I'm running. The problems occur the next day, when I try to go farther. Or the day after that. By the time I actually feel the damage that I've done, I'm thirty miles too far down the road to do anything about it. Then, your only remedy is rest, and in the face of a major race, rest may not be an option.
You must learn to anticipate problems before they happen. Very often, however, you'll find that the only way to learn this skill is to make mistakes in the first place. In my case, I've found several warning signs that tell me there might be trouble down the road. When certain muscles in my legs start to ache, I know it's time to back off. It took me many years, thousands of miles, and lots of unnecessary injuries to figure it out, but I know it now. All I have to do now is pay attention to the signs when they occur.
And figure out how to stop eating before it's too late.