Paranoid???

Drinking water like crazy and producing very little output. Not experiencing any pain. Only five weeks post-op and no weight loss this week either, which I'm assuming is water retention. Cause for concern or over-reacting?

Depends on what "little output" you are putting out.  I certainly would watch for other signs of dehydration.

Definitely something to keep watching.  If this continues, I would suggest calling your doctor.  Avoid salt, push fluids and keep an eye on things.