Have you tried having a snack before bed? A complex carb and protein snack may improve your blood sugar during the night. You may have blood sugar that drops then rises in cycles. A snack or even a glycemic drink like Glucerna may give your blood sugar some stability if it needs it.

My tinnitus appears to fluctuate with my blood sugar. My tinnitus will spike just after eating something. A cold drink can also kick it off.