It actually sounds like Dawn Phenomenon, which is sort of the biochemical opposite of Reactive Hypoglycemia. If you eat enough carbs (more than your body immediately uses for energy during the day), a certain amount of glucose will be stored in the liver as glycogen (muscles also store glycogen, but it doesn’t usually affect blood sugar). There are three times when the liver is especially good at dumping glycogen back into your system because it thinks you need the fuel: when you are stressed out (serious physical exercise; serious lack of sleep; psychological trauma/stress; etc.); when your blood sugar is too low (and you have a healthy glucagon response, which not all diabetics do); and when you wake up.
The long and short of it is pretty simple: immediately before or after you wake up, the livers of many (if not all) people dump glycogen trying to be “helpful.” This raises blood sugar. The body is trying to make sure you have enough blood sugar (and stress hormones) to get you up and going, which is helpful for most humans, but especially unhelpful for many of us diabetics. That very much sounds like what is going on with you! It certainly goes on for me as well.
Two things that are known to help with this for non-insulin dependent diabetics (and some insulin-dependent diabetics as well):
reduce total daily carb consumption and increase exercise until the liver no longer stores enough glycogen to be “helpful” (this is the basis, more or less, of the so-called “nutritional ketogneic” diet, and for typical adults usually means about 30g or less of digestible carbohydrate a day–more for those who are very physically active);
and use one of the handful of oral medications which blocks (to some extent) the ability of the liver to dump glycogen (Metformin and Metformin ER/XR are the primary oral agents used for this purpose), which also has the benefit of reducing stress-related BG spikes.
Many insulin-dependent diabetics on pumps (or split doses of basal) increase their basal insulin rate in the mornings before they wake in order to reduce this effect.
There are some other causes of high BG in the morning (fasting specifically): insulin resistance increases with stress hormones (which your body helps you to wake up with, unfortunately for many of us); reactive hyperglycemia, or Somogyi Effect, which is when the body dumps glucagon and glycogen in order to raise BG in response to a hypoglycemic effect while asleep.
Reactive hypoglycemia is when (usually in Type 2s or Pre-D) the body produces so much insulin in response to food intake (and associated BG spike) that the body “overshoots” and ends up in a mild to moderately severe clinical hypoglycemic episode (so approximately 50-70 mg/dL). Usually experiencing hypo symptoms will result in stress hormones (including adrenaline) being produced by the body, which should (hypothetically) raise BG (thus, Somogyi effect and similar).
That was a really long answer to a fairly straightforward question. My own personal experience is fairly simple: I’m an early Type 1 who has significant-enough endogenous insulin production that I’m not on insulin therapy (yet); & I have pronounced Dawn Phenomenon, especially when I was diagnosed (180-200 mg/dL on waking from 90 mg/dL at night). Three-fold treatment has really helped with my morning numbers: I take Metformin ER, which has a major effect (about a 20-25 mg/dL swing of BGs in the morning when I’m taking it vs. not taking it); I eat a fairly low-carb diet (about 50-60g of digestible carbs per day); and I exercise a lot. All three of those things reduce DP by either limiting liver glycogen release (Metformin) or starving the liver of glycogen (low carb and exercise). Putting those options together has really made a dent in my DP (i’m usually in the 95-115 mg/dL range now, with an A1c of 4.6%…so my fasting BGs are still my highest numbers).
Hope that is helpful!