What temp did you steep the specialty grains? Most of that will not ferment. Also be sure you're correcting your gravity readings for temp. Mid fifties is cold but should not have hurt the yeast. I would think two packs would be enough, I would expect this to finish closer to 1.020 ish. 1338 is known to be slow, it'll do its job in time. As you've heard before......RDWHAHB!