Deb,
according to Cutler, not supporting the adrenals is the biggest mistake that mercury toxic people make. So you are most certainly doing the right thing by supporting your adrenals. Do not listen to the naysayers. Of course cortisone (and other forms of adrenal therapy) have their contraindications, but its only short term until you get the mercury out.
Mercury toxic people need as much adrenal support as they can get.