I can only offer super-basic advice. I had a friend say temping didn't work while she was using a children's vicks thermometre, not a BBT and drinking loads of alcohol.
If you've already tried though, I'm not sure I can offer you much more advice than to use a good thermometre and stay at it for a bit. I've found my body's not uber-sensitive to movement throughout the night or even into the early morning. I can get up and pee and get up to night nurse and change beds 3 xs, etc. and still get consistent temps when I take timing into acct (that is, I may have a temp that is .1 degree higher than usual, but that's usually explained by me taking my temp an hour later). When I first started temping I though I was all over the place until I found a time that worked for me and then all the random temps became relative and made sense.
I'm not sure what your sleep disorder intails, but if you could set a quiet alarm for a bizarre time when you are asleep (like 4 am perhaps?...perhaps not) and take it then or after you've been asleep for 3-4 hours and temp without thinking about it then rolling back over to sleep, that might work. But I don't know your situation or how much you might want to go out of your way to try to make it work.
I'm not familiar with OPKs, but they may be able to confirm or deny O in some way?