Fellow newbie here. 3 months in, but I remember the first nights pretty well.
I'll reinforce a couple things others have said above. Getting the mask sealed is the foundation for everything working right. For me, this made ALL the difference in the world. If the mask leaks the machine increases the flow rate in response, trying to keep the pressure up. This creates the feeling of "all that air".
"Breathe normally" - this is what I kept thinking to myself. But it isn't something we keep track of - we don't even know what normal is. For me, I realized that when I breathe "normally" I use my diaphragm(<-- thank you spell check!), and I wasn't doing that when I was using the machine. This helped immensely.
Regarding the feeling that 4cm is too much, I was very lucky to see this post during the time I was feeling that way about my 5cm min pressure. Truth is, 5cm wasn't nearly enough as time went by.
palerider wrote: ↑Tue Jun 19, 2018 4:11 pm
You've managed to psych yourself out. There's very little air blowing when the mask is on your face. Sure, when you take the mask off, the machine revs up to full speed trying to build pressure... but when you put the mask on, it slows WAY down, to a super gentle low pressure. 4cm is what you get by sticking a straw 4 centimeters (1.5 inches) into water. if you can do that, and blow bubbles, you can overcome 'all that blowing air'. Even at a pressure of 20, it's not enough to blow up a balloon.
My recommendation is to focus on the mask leaks first. I'm not familiar with your machine, but I'd bet that it has a "leak test" mode like mine does. If so, use it. And a tip: if your machine does have a mask leak test, run it for a minute or so right before you start your therapy for the night. After the pressure of the leak test, you won't even be able to tell the machine is running at 4cm.
Stick with it. And good luck!