The question is, are you tired?
When I was taking Pred I was like a hyperactive child overdosing on articifical colouring. Two or three hours of sleep was my max, but I never felt tired, so I found the best thing to do was keep busy (cleaning became an obsession for me!) and not worry about losing sleep.
However, if you are exhausted, it can be incredibly frustrating not being able to sleep at night. I'm not one for taking uneccessary chemicals if I don't have to so I wasn't keen on taking sleeping pills. But I have had improved sleep with natural sleeping pills. You can find them in most pharmacies and they are made from hops and chamomile etc. I find them to be very effective. Just take them an hour before bedtime (I would usually then have a nice hot shower to aid the process) and then get into bed feeling all relaxed. Try some deep breathing, and focus on the words "calm and relaxed" repeat these words over and over and try not to think of anything else. It's hard and takes practice, your mind will want to wander, but I PROMISE that it helps.
Good luck!