Just starting to chart bbt but I get up a lot and don't wake at the same time..

This morning at 6 am I temped at 96.3 (and I had a fan blowing on me) then I got up to pee (which I do a lot) and went back to sleep then woke up at 10:20 and temped at 97.7. Which temp should I use? Should I set my alarm for the same time everyday?