Yeah, wearing a hose strapped to half a Darth Vader mask feels weird for a while, but it really doesn't take long to get used to it. The first time I used mine I woke up with the tips of my fingers and toes tingling. The doctor said that's because they were getting a normal amount of oxygen for the first time in a long time.

Another suggestion would be to try using the mask while taking a nap. It might be easier to get used to it that way. Or use it for a few hours each night and work up to wearing it all night.

There are a lot of ways to get acclimated to it. I think I was fortunate in that I didn't have much trouble. Best of luck to you, hope you get some great sleep.