Amended Return 'As Of' Date Changed After 16+ Weeks But "Where's My Amended Return" Tool Shows No Information

Faxed my amended return in July and finally saw movement yesterday after 16 weeks of waiting. But the only thing that changed was my 'as of' date moving from July 15 to November 26. So frustrated right now because I thought something would actually happen at the 16 week mark. I checked the "Where's My Amended Return" tool today and got this message: "Your amended return information is currently unavailable in this application. It takes up to 3 weeks for an amended return to show on your account. You can generally expect your amended return to be processed within 16 weeks from the date we receive it. Check the date you filed your amended return and try again later." This is driving me crazy because I've already waited the full 16 weeks they mention! I faxed it in July, and it's now been over 16 weeks, yet the only update I've gotten is the "as of" date change. The IRS website is telling me it should be processed by now, but nothing is happening. I can't even get any information through their tool. Has anyone else experienced this? Does the "as of" date change actually mean anything significant? I was expecting to at least see some progress or maybe even receive my refund by now. This waiting game is unbearable.