I use a CPAP, Pacifica.
It's a love/hate relationship - I love the positive affects but hate using it
By the time I decided to bring up my fatigue to my PCP my quality of life was nil, I was no longer functioning, all I did was hold the couch or chair down and slept. I had also quit dreaming - it's such a weird feeling, as if there is nothing but darkness and emptyness (hard to explain).
I rarely take naps and if I do they are much shorter. I thought my MS was progressing - after taking a shower I would not be able to blow dry my hair, I was lucky to just get dressed before I needed to go sit down. As I said, I became non-functioning.
You might have an adjustment period but keep trying. If your consistant you will see the benefits. Depending on how long you have had sleep apnea it could be several months before you see that diffrence.
Good luck!