When I was on high dose steroids for pneumonitis after radiation, I could not sleep at all....sleeping pills, benzos, nothing worked. Finally, one of my doctors prescribed Elavil and I was able to get some sleep. Maybe ask your drs about Elavil to see if it would be ok for you.
Insomnia is horrible, I'm sorry you are going through this. I long for the days, long gone, when I would go to sleep at 9 and wake up at 7. sigh.