@ZipLine-- I had the same problem due to prednisone side effects. I think that prednisone is the same thing as hydrocortisone. They're both corticosteroids.
I was also on hydrocortisone for a while as well and experienced dizziness and fatigue. Sometimes the dizziness also affects eyesight. Do you have dizziness on hydrocortisone?
I think the worst side effects of the medication however are the weight gain and bloating. It wears off after the treatment is complete. But for someone who has to use steroidal medications frequently, it's a nightmare.