Of course it's okay. I guess I don't have a fear of dying in my sleep but I do have some sleep breathing issues, and anxiety that's both general and episodic, I used to,have nightmares a lot and, i don't know, going to sleep does involve a kind of surrender and loss of control that can be tricky for people w anxiety. That whole letting go and feeling of falling. If you've ever woken up all hot sweaty uncomfortable anxious i guess i always fear that when letting go. Anxiety is about control.