Normally, apple cider vinegar works great for my indigestion. But it wasn't quite enough this time. So I decided to gnaw on a little bit of ginger, and that seems to be doing the trick.
Side note - since I began adding magnesium chloride (the main ingredient in a concentration of liquid trace minerals) to my water, my digestion (and therefore lack of indigestion) has improved drastically. Although tonight was different, I rarely need anything more than just this water to digest food properly.