Sleep apnea or distracted by oral device?

Hey guys!

So I got an oral device to treat my mild sleep apnea. I got it about a week ago and had some issues with soreness and some pain so I had to go back yesterday for some adjustment on the device. Last night, I finally got to go through the whole night without pain or soreness! So that's quite a relief and hopefully I don't have to go back for another adjustment before my follow up appointment already scheduled for about 3 weeks form now.

Now I got a question. I went to bed last night and had difficulties falling asleep. I understand having a big thing like a device in your mouth is something that takes time getting used to so I'm ok with that. The issue is I'm not sure whether I'm really asleep and if I am, I don't know if it's just light sleeping and having difficulties getting into a deeper sleep or I was just somehow out of it. It took about a couple of hours after I went to bed before I felt like I may have fallen asleep or I was just out of it for some reason. It's hard to remember exactly what happened and when and how long. I think I finally fell asleep but not sure what time. I went to bed around 12:30. I remember being awake at 2:30 in the morning and thinking, "I'm going to have to take a sleeping pill or I may not sleep tonight." So I went ahead and took one. I went back to bed and what seemed like a short time later, it was already 4:00! So I don't know if I did fall asleep but it doesn't feel like it or if I read the clock wrong and it was maybe 3:30 when I took the pill. So it was 4:00 then it was at least 4:30 and I was worried about not getting any good sleep so I figured, "well, I stuck with the device longer than I used to last week when I was having pain so that's better this week!" I thought I'd be fully asleep by at least 4:30 and I didn't think I was so I had to remove the device then next thing I knew, I was feeling real tired and finally went to sleep for sure. I know because I had a dream so I got some real sleep without the device and I don't remember waking up since taking it out.

So I have to wonder if I really got some sleep while the device was in or was my mind playing tricks with me? Does sleep apnea occur during light sleep that I was lightly sleeping then the apnea woke me up at 2:30 or 3:30 or could the oral device be waking me up completely? I thought sleep apnea does occur in deep or REM sleep or does it happen at any cycles? If I woke up from a light sleep then it could've been the device waking me up, maybe? When I breathe with the device in, I can really feel the air coming in my mouth so I'm hoping it's not sleep apnea that gave me this issue and made me wake up last night and I'm hoping it's just the device and I needed more time to get used to it.

I'll probably feel different later today but right now, I feel pretty good like I got some nice sleep but not sure if it's enough. I know I slept great from at least 4:30 to about almost 9:00 this morning without the device. Maybe I slept better than I thought?

Thanks!