I think the most important thing with any mental disorder, chronic illness, or sleeping disorder is supportive and understanding friends, family and loved ones.
My SO has fibromyalgia, this means she lives in constant pain. Some days she feels like I do most days, some pain, but it's not distracting, it doesn't make life harder. Some days everything takes more energy and more focus to get it done. And some days it's crippling. And you can never tell what kind of day it's going to be.
The way I make it tolerable (I hope) is by accepting that this is the situation, and that some plans just don't work out. I don't let it get to me, it's just something that happens. We deal with it.
It's like someone catching a cold, and canceling. Only it happens a bit more frequently than people usually catch colds.
Since meeting her I've also become a lot more accepting to people canceling "just because". Maybe they woke up in a shitty mood. Maybe work was really frustrating. I don't want people to force themselves to meet me, well, unless it'll help get them out of the bad mood.

Your situation is not that different. You might not be able to get any sleep, and tough, will need to sleep over something you scheduled. Sure, you should work on fixing it, but in the meantime, work on accepting the situation, and if you accept it, and are open about it, you'll find the people that will also be accepting of it.

Lastly, it wasn't listen on the things you tried, so I might as well throw it out there. Doubt it'll fix everything, but on occasion it might help.
Try imagining landscapes before going to sleep. Create worlds in your mind. I usually end up floating across a field, and off a cliff and over an ocean. Avoid an inner dialog, don't say to yourself "And the trees can be purple, and the grass red" just see it in your mind's eye.

Good luck with the new therapist!