BBT debate/ confusion

Jessica • Edd 11/9 #3 after losing 6 mo old daughter last July & having a tubal reversal in September. Hoping for a rainbow baby!
Ok.  So everything says you should take bbt in bed before you even move at the same time every morning. Bbt is supposed to be the lowest body temp you have for that day- your baseline.  What I've noticed lately is that if I am bundled up in the covers or cuddling with DH it affects my bbt significantly and I wonder how the heck I can figure out an accurate way to chart this?!
​For example.  Today I checked as soon as the alarm went off 97.23.... But I was feeling hot cuddles up with DH.  I uncovered and after a few minutes retested when my snooze alarm went off.  96.87.  So if bbt is supposed to be lowest, which do I use?  
​Even so I've still had a big enough spike to pinpoint ovulation but it just seems so inconsistent and frustrating!