Sleep Apnea Treatment

I’m just curious, for I am most afraid of dying while I’m sleeping. I know that most people prefer this type of death for, as they say, it is painless and “the best way to die.”
Although, I wouldn’t really consider it as a “phobia” because I can still sleep perfectly; My fear hasn’t affected my sleeping habits whatsoever.
I just need the name of that fear, some background information or some other facts you can share.
Please and thanks. :]

I have had sleep problems for years. When my only child died from cancer, my Dr put me on xanax. After 5 yrs of 6mg of xanax a day, I decided to go to detox. Now, 6 months after detox, I am unable to sleep. It takes me 2 or 3 hrs to fall asleep and i wake up every 2 hrs. I am so tired and weary. Dr. put me on ambien and then lunesta. The side affects were horrible. Everything from headache to lousy taste. Now Dr. has put me on 1/2 mg xanax a night. It works but I am afraid of needing more as time goes on. Anyone that has an answer, please help me