Sounds like things are complicated by lots of factors.
A diagnosis is great for peace of mind - as hard as it can be to accept it is nice to be able to put a name to it. Nice - but not necessary, you can try symptomatic treatment, and that might help work out whats wrong. Rather than trying to get a diagnosis, maybe you can try to get something that will help you. If sleep and muscle twitching are worrying you, then can you get some meds to help that?
It can take a long time to get an accurate diagnosis, esp with things as complicated as your situation sounds. Try to be patient with the doctors, they are human - they make mistakes, but a lot of them are good at what they do. If they all say the same thing, do you think it might be true????

It also might be a good idea to see a T about how your thought are affecting your health, and to see if they can give you techniques to deal with your racing thoughs and conversations.

Sorry if this is harsh, it's just my opinion, I too am human and make mistakes
All the best for getting the treatment you need and working out what is wrong.