This may not help directly, but you're not the only one.
My insulin sensitivity seems to change for no obvious reason. It might be weather (more required when cold?), injection sites, mood, stress, sure there are others.
You may have to adjust your QA ratios/corrections and/or BI and it might take while.
Over last few weeks, my Levemir has increased from 9U am and 8U pm to 12U am and 12U pm as too many BS were over 10. Today trundling along about 4.2 so may look to start reduce of BI.
It's a pain but don't panic and only change one variant at a time, as in DAFNE.
Hope this re-assures.
J