How can I boost my adrenaline glands while taking 5 milligrams of prednisone? I am fatigued and I have stills disease and high blood pressure.

No way. Prednisone at that dose will partially suppress your adrenal glands. There is no way to avoid that suppression and no way to boost your adrenal function, except to maintain overall good health and nutrition.
You can't. You simply need to comply with your prednisone. Your adrenal cortices will regenerate normally when you are able to go off your medication. Loss of adrenal cortical hormones isn't the cause of your fatigue. Perhaps you will be a candidate for some other treatment for whatever form of Still's you have.