Sorry, Laura, didn't see the messages here.
I think we had this craziness for 2-3 weeks until I decided to all for advice here and we went to 4-5 hrs A time and 2/1 transition. It was much easier to focus on one nap and do a CN with APOP. Just like yours, my back was killing me and my nerves were not ready for that at all ; )
After I pushed A times really far, she was exhausted and didn't fight the nap. DD also had a cold, so I went with the flow, but kept extending her A time after I saw she was fighting her nap.
That was one of the most stressful times. Even though all first 8,5 months we were super sleep deprived...