The consensus is that I've got a bit of a cold, but that he suspects the business from last night with the abdominal cramping and the sweats was either food poisoning or a case of stomach flu. It seems that there's a nasty stomach flu bug going around.
After the doctor's appointment, I went over to Swiss Chalet and had a bowl of chicken soup for lunch, with a small chicken sandwich. Very nice, quite satisfying, and enough of a meal to keep me happy.
Let's hope I have a good night as well.