My mom got cdiff after gallbladder surgery almost two years ago now. It took them a long time to figure what it was but when they prescribed flagil it improved pretty quickly, but her gut was a mess for months. Then they did a colonoscopy (routine, bc she's older and her father died of Colin cancer) and she relapsed a few months ago, and is just now recovering again.
It sounds to me like you are doing all the right things. I would think the breastfeeding and antibiotics would be a powerful combo (I actually even suggested to my mom that breastmilk -- my sisters -- might help her, because of its positive impact on gut flora, but she was grossed out). It is a scary disease but there are lots of treatments. Sending positive thoughts!