Maybe the body is reacting to the sleep deprivation by releasing more stress hormones? Noticed myself on days I only get 3-4 hours sleep that right in the morning I wake I might still be at 4-4.5 when measuring while still in bed. But within just 30-60 minutes after, when starting to shower/move around, then my bg can have shot up to 7-8. And that without having eating anything yet.