Probably a stupid question...

Vee
But, I'll ask anyway :). 
​I'm off from work today and decided not to set an alarm to take my temp. My BF woke me up to take it, and I did. I then realized that I hadn't slept enough and thought that I would go back to sleep for a few more hours then take it again b/c I'd be more rested then. 
​So, I wake up, take my temp again but now it's a lot higher than before. 
​I'm currently on CD 18 (which should be O day) so now I'm confused as to which temp to log. Help!