Thanks.
Our blood glucose levels are controlled by hormones (as you know) with insulin being one of the biggies.
Apparently (I have never timed this!) if we go more than 5 hours without food, the liver often steps in to give the blood glucose a wee boost, by 'liver dumping' glucose from its glycogen stores, into the blood stream.
The fact that you woke up at 5 am feeling like that, with a bg of 5 something, suggests a few things to me (remember, I ain't mnedically qualified). Firstly, your bg probably dropped in your sleep, low enough to trigger a 'liver dump' and what woke you was the result - the impact of that. So by the time you woke up, your body had already raised your bg to the 5s, which is perfectly acceptable. (but it is worth noting that for me, dreams and anxiety can do the same thing. I went through a period a while back caused by work stress, where I was waking up in a similar situation, and when the stress was dealt with, the flustered wake ups disappeared too)
So, there is
something going on with you that drops your bg down in the wee small hours, that triggers a liver dump.
It may be as simple as 'my last food was at 8.50pm, and had some carbs in it, so my bg was dropping at 5am, and my liver decided to dump some bg to bring it back up.'
As a suggestion, try having a non-carby snack just before you go to bed. I sometimes use peanut butter (on a spoon, not a cracker) or a slice of cheese or some nuts. It may help. And worth doing for a week or so, because the body gets into habits, and it may take several days for it to realise that the 5am surge isn't needed any more.
Also, if you do eat something at 5am, try nuts rather than a flapjack. If your bg is 5, you don't need carbs, and the nuts are nice and slow release, so they will gradually drip feed you til morning, rather than making your bg shoot up, then drop, in typical carb fashion.
Regarding Dawn Phenomenon, it is also caused by hormones, and it happens to everyone to some extent. It is just the body's natural 'wake up call' where hormones are released to prepare the body for the day's activities. And, in a person with well balanced normal hormones, the DP is a teensy rise in BG. In a person with screwy hormones, the DP can be bigger and more 'attention grabbing'.
My own experience is that my body gets into habits. The more I allow it to liver dump, the more trigger happy it gets. And the more I allow it to DP, the bigger and more over the top my dawn phenomenon bg rises are. Yet another reason I avoid carbs!
Hope that helps.