I've caught my blood sugar high (272, 286) but it usually had a tendency to run low not high. I don't take insulin. Could something be malfunctioning?

Yes, two things. First, your body -- as a glucose above 200 indicates diabetes and needs attention from your physician. Why are you on corticosteroids which can partially be to blame for your high glucose? By the way, no one's blood sugar runs "low" unless on meds for diabetes. Nex, your mind -- of course something is malfunctioning. You're not thinking clearly if you don't realize you need to see your doctor now.