Better concentration with CPAP while being awake

So it's now 15 months on CPAP, with very good AHI (always 0.5, even on an official Polysomnography with CPAP), no snoring. Sleep quality is good according to this Polysomnography (done in May 2017), which is different from a WatchPat-200 last year (wake up 2-3 times per hour).

What's better ? Much less sleepy around lunch. Much less tingling feeling in my head in the morning. I can say so because last night I did not sleep with the CPAP due to a blocked nose.

But I am still dead tired, with all cognitive problems: concentration, forgetting appointments even when I note down carefully, thinking speed, decision, multitasking, being angry very easily, headache all the times, low energy

Psychological doctors, after 10 months doing research have tried to label me with ADHD or Depression, and now given that I don't match they'll try me with Autism. It'll take another 6 months I guess.

One thing no one believes me: why with CPAP while being awake can I concentrate much better, with much less headache. Also with deep breathing from Taichi helps me in the evening when I feel my brain is dead tired.

you can use a general non recording o2 meter during the day
If your o2 levels are ok, it's a placebo feeling better with cpap during the day. If your o2 is down, it's off for more tests.

or get a recording o2 meter cms50f from ebay china for $50. some have quick delivery. I got mine in a week. It would be easier and cheaper than trying to get a doctor to organise a 24hr o2 study.