BBT question

I was hoping for some guidance from those who have been doing their bbt for a while now. I was told to test my bbt first thing in the morning before I get out of bed but, my problem is I go pee anywhere from 2 to 3 times a night. Should I test it the 1st time I get out of bed, even if it's only a couple hours I go to bed, or wait until I get out of bed for the last time to get ready for work??  Any help would be greatly appreciated : )