Take golf ball size pinch of it, let it sit for an hour or so in your kitchen and then run it part way through your oven. If there is yeast there, it will rise in the oven by some visual amount.
If it turns out that there is not, all is not lost. You could still mix that dough back into new batches about 10% at a time. Just put it in in smallish blobs and let it mix in. so for example if your batch is based on 25 lbs of dough you could put 3-4 pounds of “flat” dough into the mix of a batch. Just make sure it is well mixed!
