This is a question that we talk about often. Lupus itself causes fatigue but we can't sleep well. THen, as you said, add to that the meds we take and many of us have issues with sleeping (or not sleeping). I wish I had the answer for you. I took a medicine for my fibro that really worked to help me sleep however I eventually maxed out on the dose and then it didn't work anymore. I too am on 60 mg of pred. daily and I try to take it early in the day but I am now back in the same boat as you.
I will be listening patiently for suggestions because so far nothing is working.