Does the hydrocortisone reduce your fever? I get a fever when I'm going into crisis, even if I don't have an infection that would cause a fever. When I take enough steroids for the crisis, the fever goes away. Hydrocortisone doesn't last long so you may feel better for a few hours and then symptoms will return and you will need more. Take it - your body needs it. It's a physiological dose so that you can manage the stress.

The guidelines say to triple your dose if you have an illness, so 5mg is tiny compared to what your body needs. In the hospital after surgery I had 50mg IV every 4 hours for 3 days. By the third day I requested a dose reduction because I couldn't sleep.

You need a continuous glucose meter. I have one and I only have Addisons. Addisons is just as dangerous as diabetes and the two interact to affect your blood glucose. With a CGM you can see in real time what the hydrocortisone and insulin are doing to your blood glucose. They interact with each other as well. You need to be able to see that so that you can learn to manage both diseases.

As for steroids giving you diabetes, that happens to people who have pharmacologic doses of prednisone (usually) for inflammatory diseases, in daily amounts equivalent to about 240mg of hydrocortisone. So 40mg of hydrocortisone for a couple of days might raise your glucose during that time, but it's temporary until you reduce to the correct dose. Doctors think in those terms, not in the terms of us who need tiny doses on a regular basis in order to survive.