I've been in Pennsylvania for most of the last 6 weeks, coming home late Friday, leaving around noon on Sunday. My wife was getting worried about Bella, our older dog--she was lethargic and on our usual walks was lying down to rest early on--she never does that usually. Wife had begin taking the two dogs separately, so Angie could at least get some exercise. She was worried enough that she was about to make an appointment with the vet.
Apparently the only thing wrong was me being in Pennsylvania. We took her to the river together, and there was no sign of any problem--She ran, swam, kept bringing me a stick to throw into the river, and was completely energetic and normal.