You might want to consider going on a parasite cleanse. parasites are known to disrupt sleep. If you don't have any underlying health conditions that would cause sleep disorder and it appeared out of the blue with no change in home and work environment and stress level, then a parasite cleanse just might do the trick.
I assume you've had a full panel of tests run: full blood, thyroid, hormone, etc...
It might even be a good idea to do a liver cleanse/flush.
In the mean time, you can try phosphidtyl serine at night to help lower cortisol levels. Raised cortisol levels at night disrupt sleep.