I believe one of the symptoms of heart failure, depending on the stage of advancement, is swollen ankles and the collection of fluids in the abdomen. Perhaps, in addition to some new adipose tissue, you are experiencing some of that. Note that the kidneys need a minimum of blood pressure to operate efficiently, below which they cease to maintain blood pressure, filter fluids, and reduce hydration in the body when they need to. So, again, the accumulation of bodily fluids.

I'm not suggesting this IS what you are experiencing, but it's worth inquiring from a professional.