Sleep apnea, little REM sleep, insomnia?

I have the same problem. I am on a cpap machine I use the full mask. If there is a problemu will feel better right away. I think that it is all linked to oxygen in the body. I pap machine is like a small humidifer which u breath in thru your nose. do u have sinus problems? If your nose is plugged all the time, a full mask will force u to breath thr your nose. The first night I slept 12 hrs. I never woke up. I found out that I was exhausted, maybe half dead and did not know it.