Running

Can't see anything that would link a shortish run with 2 days of stomach troubles. Any damage done in 10 miles e.g. dehydration, bonking should have righted itself well within a day, or even a meal. My guess would be that a minor bug of some sort had been picked up beforehand, and maybe taken a foothold when the body was under the stress of running.

Of course, ianad.

I support this hypothesis. All of the above may influence having the shits during the run or for a couple of hours after but I don't see any of them causing something that lasts for a couple of days. Hope you feel better.