I've been using melatonin for several years now. 3mg at bedtime.

It is also implicated in glucose control and exists in the pancreas.
However its link to functions there are not proven yet.

Melatonin is depressed by age, low B12 levels, and some drugs.(SSRIs and beta blockers, and drugs that depress B12)
Methylcobalamin is a cofactor in melatonin synthesis from the serotonin precursor. Melatonin doses in some studies are quite high. I wonder if many people could tolerate that.

I had a low grade inflammation along the gum line which was just fixed. It might be this low grade infection was causing my elevated sugars. I just had the crown fixed that caused that.

Three things piling up on each other. I am going to wait 2 weeks and reintroduce the NAG. And see if my sugars increase again.
In any event the NAG was not doing much positive as it was, at the time. But that was only a week or so. Maybe too soon for it.

I have also stopped the amitriptyline too.