Shrinking bread problem??

I've baked all of our bread for many years although I am certainly not an expert.  For the past couple of years I've settled on either a whole wheat loaf with walnuts or pecans and currants, a round peasant loaf baked on a stone or baguettes in a perferated pan but again on a stone.  The last few months I've experienced decent oven spring but by the time the loaves come out of the oven they have shrunk considerably.  --This is true of all three breads.  The crumb is pretty dense.  I'm using the same recipes and flours, same SAF instant yeast.  I've not checked my oven temperture but wonder if I'm over baking or over proofing.  We use Bob's Red Mill or KA AP flour and Bob's Whole Wheat flour.

Any thoughts would be appreciated.

Gary