I suffered something similar to you, i would awaken every few minutes when ever i tried to sleep. Mine was anxiety base and over worry from the sever side effects i was having from PPI meds. I was severely stressed was loosing hope, depressed, anxiety you name it it was happening to me all because of PPI side effects, even sever breathlessness. In No way am i saying that yours is stressed based or it could be physical underlying for your condition. But unless you reduce your stress somehow it will only compound your problem. ayaou must try and relax and calm down, over stressing like i did was not helping and i had to pull myself together because loosing it was not the solution. Ands i am mentally very tough but found myself in a situation neither could i or the doctors ever imagined.
talk to your doctors and discuss such issues with them, damage to the vague nerve could certainly be a possible explanation for your symptoms.
I hope you find a solution soon, i can sympathise with you.