Diabtes symptoms and conditions

My doctor prescribed me Prednisone on May 3. I'm on 10 mg. I start out on 3 tabs 2x a day for 4 days, then 2 tabs 2x a day for 3 days, then 1 tab 1x a day for 2 days. I was put on this for a sudden attack of joint pain/stiffness/swelling of my elbows, wrists, hands, knees, ankles and feet. I was in extreme pain. So far this drug has given me no side effects other than needing to urinate a little more often than usual. My pain is gone, as is the swelling. I'm almost scared to go off this b/c of the fear of the pain coming back. My blood tests came back on Friday and my doctor told me that I had Rheumitic (sorry, I know that's spelled wrong) inflammation and if the pain did come back after I stopped the Prednisone that I'd have to do more blood tests. I just turned 30 and I'm scared to death what else might be wrong with me.