Prednisolone does cause mood swings. I should know! Been on it for nearly thirty years with Crohns Disease. Don't know about stopping the medication, maybe it'll take some time for those mood swing effects to wear off.
With me it's anger and irritation, impatience and desire to be on my own and reject company. See, its all the negative, hateful emotions/moods, nothing positive at all.
I don't have diabetes, I normally post in the CROHNS DISEASE and DEPRESSION messageboards but just caught the heading of this thread as it was the most recent one, on the general boards and contents page, for DIABETES, and thought I may have something useful to contribute.