I just ready Taking Charge of Your Fertility, and am hoping to start temping and charting seriously on my next CD1. But, I have a question. I shoot to take my BBT around 7:30 every day...but sometimes I wake up at 4am, 5am, or 6am...I am not a good sleeper. I think the rule is you are supposed to sleep at least three hours before taking your BBT. So, if I go to bed at midnight, awake at 5am (but don't move out of bed or anything) and then go back to sleep, can I still take my BBT at 7:30 and get an accurate reading?