Phobia.

Dear doctor, I have been suffering from anxiety disorder. Along with that I also feel that i have a phobia that I may die during sleeping time. Whenever I am alone  i get nonstop thoughts of death and could not come out of some fears but I  fear when i sleep in AC or Closed room. Is it really dangerous? i feel that i will die in a closed room whether AC or NonAc? Sometimes  when I  sleep alone in a room my anxiety triggers.i have  nonstop thinking . Why do I think like this? Earlier I was not like this. Only for last 5 years I became like this. Please help me to come out of the problem. I used some medicines but not completely cured.

Phobia.
Psychiatry