Precious is her little black pomeranian.

I'd go with the advice the others have given here, give that a shot.

I'm a medical transcriptionist, so I looked in one of my resources for symptoms of CHF. This is what I found:

Symptoms of Congestive Heart Failure

Along with edema (swelling) of the lower extremities, the most common symptom of CHF is shortness of breath and often, fatigue, weakness, and the inability to perform physical activities. Weight gain from the excess fluid is another common symptom. Some people begin to cough up pinkish, blood-tinged sputum.

That pertains to humans but I'd imagine symptoms might be similar in animals, fluid retention seems to be a big pointer. If she seems heavier (might be harder to tell in that little puffball).

I hope your mind is set at ease more though, and that Precious gets better quickly!