For now, I suggest you commit to practicing every day while awake.
First, I want you to examine the mask carefully. The Resmed Mirage Quattro has an anti-asphyxiation valve. (You don't need one on a nasal mask, because you just have to open your mouth to avoid asphyxiation

). Right above where the hose connects, there's a silicone flap. The force of the air in the hose pushes the flap to seal the anti-asphyxiation port. If there is no air in the hose, there's nothing to push that flap to seal off the port, and and you can breathe the air in the room from that port. So there's NO WAY that you can suffocate in this mask. I hope that helps a little for you to relax, but when I was getting used to it, it only helped a little. I still had panic attacks from
claustrophobia. Nevertheless, it's important to understand how the mask works. All full face masks have some sort of anti-asphyxiation valve.
So here's what you do.
First, you need to increase the minimum pressure to at least 6. Almost all of us feel like we are suffocating at 4. You have to do this in the clinical menu, and I'll let someone else tell you how. That will go a long way toward less sensation of suffocating.
Now you should sit or lie in a comfortable position and wear the mask with the machine on for 30 minutes at a time. Watch TV, listen to music, read a book, practice mindfulness or relaxation exercises. If you have a panic attack, take the mask off, calm down, and put it back on until you have clocked 30 minutes in the mask. If you can't stand to have the mask on even for a minute, hold it against your face without the straps, knowing you can always move it away from your face if you panic. The most important part is to always begin again if you take it off in a panic.
After a day or two, when you feel that panic begin to build, promised yourself you will only take it off after you have counted to 10 slowly. Count to 10 slowly then ask yourself if you really need to take it off at all. Take if off if you need to, calm down, and repeat. Or try counting to 10 a second time and see if you really need to remove it. Your goal now is to increase the time before panic attacks. When you can easily go a half hour without taking off the mask, extend the time to 1 hour.
Meanwhile, you should also be trying this at night, in bed, but where you really work on extending the time is during the day. When you can get to 1 hour purposefully awake, then you can switch to increasing the night time use. Same rules apply. Count to 10 slowly. Remove the mask, calm down, put it back on and start again. Try as hard as you can not to fall asleep without the mask on.
I had terrible panic attacks at first, and other phobias that didn't seem related like driving across bridges. When I finally conquered sleeping in my mask all night and waking calm and relaxed, guess what? My bridge and other phobias were much improved, too.
With apnea, we spend all night bathed in a cocktail of stress hormones as our body tries to get us to breathe. It takes a toll on us. Once the apnea is adequately treated, our stress reduces significantly.
Claustrophobia lessens or disappears.
Quitting is not an option. Your
claustrophobia alone tells you that you have very severe symptoms that are affecting your heart, your brain, your central nervous system. If you quit your efforts to get used to CPAP, you are going to have a host of severe medical issues (if you don't already). So keep going, keep working at this. You must not stop!