@pavlosn
It feels low if I go down to the 3's, and even 4's in the day, from a higher number, I always used to be more comfortable in the 5's.
I don't feel bad waking up to 3's and 4's though.
I think it's two things happening, the first one is I think my overall BG is lowering overall, and it's continuing the trend I had over summer, so I'm getting used to lower numbers, and 'lower' lows.
Secondly, I can feel my 'liver dump' (or at least some psychological dump), as when I wake up, I go from feeling tired, to pleasantly awake, as if I have just had the switch turned on as it were.
But I usually eat breakfast fairly soon after getting up, so it's hard to tell if my BG would continue up by itself, or stay in the 3's.
Maybe an experiment for a later day.
From other experiences throughout the day, I certainly didn't notice anything bad if I didn't eat, no sudden highs, so I'm assuming I used my liver dump, and kept in the 5's and 6's, and the only thing I do notice is if I further don't eat, I do feel it then I eventually go down into the 3's. Nothing awful, just I know I feel like a snack.
I obviously do use my glucose stores, as I can exercise heavily, but I come out low, then I can eat, (carbs) and I don't rise badly, so the glucose is going back somewhere.
Sorry for the long rambling answer.