Having doubts...

22 times you stopped breathing per hour is enough to cause anyone problems. You will not be 'hurting yourself' by continuing treatment, most likely the opposite. Will all your issues go away? No ones knows, not even a doctor could answer that with any certainty but at least you will be doing what you can on this side of things to try. Likely there are other issues, and this is my case as well but I know I don't like to stop breathing even 15 times an hour (AHI=15, where I was diagnosed) so I will continue to treat myself.

6 is a pretty low pressure as mentioned, and I would NOT have C-flex set on 3 with a pressure that low, 1 maybe or even nothing. You should try to turn the C-flex OFF and if you have no trouble breathing out against the pressure, I would consider leaving it off.

The Quattro is a good mask but leaves something to be desired, comfort. You are right there is a VERY fine line between too tight and leaking, I have the exact same issues but after about one month I got the straps set just right and now NEVER have any leaks, I do have slight marks on forehead which fade in about 20 minutes and a mark on bridge on nose that fades in about an hour and a half. Any tighter, nose mark becomes a sore and raw and would need a break to heal, any looser and sure to have leaks. The new FX model I think addresses this but have not tried it myself.

The main thing you need to do is somehow find out what your average pressure is during the night. Whatever that is, I would set the machine low pressure at that pressure or only 1 lower, and set the high pressure about 5 above that number.

Good luck and stick with it. Note newer machines do have some better technology and can work better overall for many people than older ones (where APAP is concerned). Keep reading these forums, lots and lots of good info here.

Also, don't feel bad about 3 years and just discovering this. I've been tired for TWENTY years and just started this 5 months ago, I have a LOT of catching up to do and most days I am still tired but overall better with the machine than without and some days I actually feel quite good, they are just not frequent enough yet even though I am breathing well through the whole night now (AHI always lower than 2, usually 0.4 to 1, which again could be pointing to other issues)