I went ahead and spoke to the veterinarian today and decided to take her in. They told me over the phone that, even with a kitten of six - seven weeks, a constant meow (even after a spray of water or a firm, but voice-raised "shhh" for several days) might indicate a problem. His comparison was to that of us humans when we were a baby: "You didn't have any way of communicating a problem unless you cried". They have gone ahead and tested her for various things and I should know something by tomorrow or, at worse, Monday. I did go ahead and get her booster shot and informed the vet that she might also be an outdoor cat once she was a bit older. He is a bit concerned about the knot in her upper stomach and said that tests would reveal any problem. I'll keep you guys posted with any other information and thanks for being here. I've got my fingers crossed that it's a simple situation that can be easily fixed.