This is Dr. Thomas, a different expert.
I have a different answer for you.
Take your temperature.
The vaccine can cause high fever.
This could elevate blood sugars.
More importantly, your sugars are too high.
You can not, on your own, rule out infection from another source, and this could range from flu to viral meningitis given your symptoms.
These would keep your sugars elevated.
I do not think it is bad insulin.
An undiagnosed bacterial infection is also possible.
I don't believe this is self treatment or time to sit around and figure it out, but that you should be examined today.
If this is a vaccine reaction, it needs to be reported as well: such reactions are under reported.
OK, so that is an initial answer….
Please use reply to expert if you have further questions. When you are ready, please click a positive rating [hopefully excellent]. If you forgot something, come back. I am here daily.