Try mixing 1 tbs of yeast to 2 tsp of sugar in a small bowl with 1 cup of water and a tbs of flour. Let stand in a warm place (75 - 85F) for 2 hours. If it does not become bubbly and frothy, your yeast is completely dead. If it froths you can add half of it to the dough you are trying to salvage.
The sugar is for giving the dying yeast a kick start and the flour for the off-chance that the dried yeast contains strains that are more partial to flour and to insure adequate food for the two hour period allowed for the small percentage of still live yeast to multiply. Over the course of several days, I often make three pounds of bread starting with as little as 1/4 teaspoon of dried yeast and no sugar not honey.That sounds like a good suggestion Bill. I'm curious what the 1 T. flour adds, although a few times I've seen proofing directions similar to that. I've used only sugar or honey to feed the yeast.
As long as you've opened the possibility of adding more yeast to the loaf to salvage it, perhaps it would be good for the OP to pick up some fresh yeast at the market, then proof it and blend it into the dough. In that case I'd use only minimal water, perhaps 1/4 C., in order to not change the moisture content of the loaf too much.
Surprised you're not a baker. Most bakery products on the east end are pretty expensive and often not of the best quality. E.G. the Blue Duck seems to be going downhill.This reminds me of a cooking show I saw many years back, Short lived and a not very talented host. He was doing a dish which had a yeast something........demo done and time for the big reveal ..........well old yeast, no rise........show cancelled shortly after. I am not a baker, but that taught me to check the date when buying yeast.