Shrunken Gingerbread

I am using a recipe from a book that uses all vegetable shorting in the recipe. It seemed very soft to me, so I added more flour. After rolling out and baking, I expected it to expand a little since there is baking soda in it. However, it actually shrunk up a little.

Any suggestions? I have a ton of dough in my fridge ready for making a gingerbread adirondack house, and I'm scared all our labor will be in vain!

Thank you.
Jen