help! I need to save my loaf.
After snooping around on this site for years, here is my first post - I could really use some help. I couldn't find an answer to my predicament in my search for past posts.
Someone gave me a sourdough starter (apparently it's a few decades old, from a local baker) last week, and I've been dutifully feeding it as per her directions. It seemed very active. I've already fed it three times this week, and it always at least doubles within 6-8 hours in my kitchen.
I used some yesterday, after I noticed it had doubled, and made some dough using this recipe: http://www.thefreshloaf.com/node/13614/walnut-sourdough 
I followed the directions, and kneaded the dough really well until I could stretch it and see light through it. But at step 11, while proofing, I noticed that the loaf hadn't risen at all. I let it go for a total of 1.5 hours, then, to see if it would perk up, but it didn't. Maybe this is normal, I thought, so I put it in the fridge to do the retarding overnight. This morning I took the loaf out of the fridge, and still don't see signs of rising.
Is there anything I can do? This loaf is my first that's entirely made with wild yeast so I'm not sure what to expect. The last loaf I made fairly successfully with a bit of packaged yeast in addition to the wild.