My OH was very ill two years ago (long story). He was on steroids for a quite a while, and he had to reduce them gradually as the doc told him he would have unpleasant symptoms if stopped suddenly. Don't know if it's the same for dogs, but it would seem sensible to me.
Dylan had his teeth cleaned a month ago, and it was discovered he had lip fold dermatitis. He had a 2 week course of antibiotics and steroids, and by the end of the second week he was quite subdued and down in the mouth. My vet said steroids can sometimes make them depressed. Been stopped a fortnight now, and he is back to normal.
I hate seeing the young vets when my older ones are away, I always worry about their lack of experience, so I sympathise with you. Hope you can get it sorted to your satisfaction.
Hugs for Ollie.
Lesley and Dylan