Your question concerning when I realize the mask is not on, nothing because I don't realize until morning, and then it is too late.
I experience the same thing, it is so frustrating. When I take it off in my sleep,I vaguely remember removing it but don't have any control, just seems to happen. Then so mad at myself in the morning when I wake up without the mask. Getting ready to go to bed now, so hope I have success tonight.
I have only just joined the sleep apnea org. Having a little trouble using that as I do keeping my mask on. How do I join mood patient powered research network, I too suffer from depression.
I have had my sleep apnea machine for almost two years now, not sure that I have ever completely adjusted to using it, if I do sleep for about 7 hours with it on, I wake up with a pressure sore on my nose. currently my problem is almost in my sleep removing the mask after only around two hours.