Nasal Pillow to full face mask

[Woodgod]

I am considering changing from nasal pillows to a full face mask. I believe I am doing some mouth breathing. I was always a mouth breather before I got my cpap. I kind of retrained myself to breathe through my nose when I sleep.
But lately I have woke up and noticed I was breathing through my mouth while still wearing the nasal pillow. I am pretty sure I do this when I get congested in my nose and don’t have a real clear nasal passage. I must try to get some more air and breathe through my mouth. Is this common? I don’t think I can use the strap, I kind of messed around with a trial one and didn’t seem to like having it on around my chin. Don’t know why. I have always though about trying the full face mask.
I finally got one and tried if for about an hour nap yesterday, it felt like it was getting a lot more air. I noticed the inside of the mask had fogged up some, is this typical? I also had a little sinus pressure when I woke up from my nap. Like a small headache, it felt like I was not used to the pressure. I changed my setting from nasal pillows to full face mask.
It really does feel like I am getting a lot more air. Is this typical and is it something I should just try for a while. I am kind of afraid to try it all night; I don’t want to wake with the headaches I used to have before starting cpap therapy. I hated those darned headaches.
Have any of you folks changed from nasal pillow to a full face mask? How long did it take to make the adjustment? Thanks for your help.