I have to adjust my own pressure as well, since I can't afford to do another sleep study (American Healthcare rocks!). The biggest difference in my sleep came from when I purchased a machine that auto adjusts based on what you need, so no one could lock me out from getting the best healthcare possible.
I know I suffer from sleep apnea (poor sleep quality, relatives have noticed me stop breathing for brief periods while asleep, loud snoring) but I literally cannot bring myself to get a sleep study done because I know it's not going to be cheap, and to top it off I don't even know how expensive it's going to be in the first place. It's not like I can't afford to pay either, I do have some money stashed in my HSA but…
If you are a bit adventurous, go on Craigslist and buy a used one with a new mask for like $100. You probably are a Large mask size.
Figure out how to adjust it and try it for a few days. Keep a written record of how you feel. See if it helps. Starting at 6 of whatever the unit is will probably be a good starting point.