one degree rise on period day??

I slept restlessly last night (my oldest woke me up at 5am and I was up for an hour after that) but I got in a good hour after that. I wound up taking my BBT at 5:30, after a bathroom break and tossing and turning, and it was down .5 from yesterday, which checks out for my period. But after I went back to sleep for an hour, I woke up at my regular time with my temp a full degree up from the 5:30 reading. Which reading would be the more accurate one?