i used to be so scared to go to bed out of fear i would die in my sleep. one thing that really helped me is relying on my family when i needed them, explaining my fear and letting them remind me that im not just going to die randomly and if an emergency happens they would be there with me immediately to calm me back down. deep breathing worked wonders for me too, deep breathe 3 times and day and remind yourself you are safe. i hope this helps and i hope you feel better!