So last nigh I went to bed around 10:30 ish and woke up at 3:30 bbt was 98.7 which is about normal for me. I never got out of bed but tossed and turned and eventually went back to sleep. Woke up again at 5:40 and bbt was 98.4 which is pretty low. Which one do I use?

Also the night before I tossed and turned all night and there were times I laid awake with my eyes closed but never checked my bbt. When my alarm went of at 6 my bbt was 98.2. I discarded that, is that right?

I'm mostly worried because I'm 12 DPO and plan to test today but if my BBT is dropping and af is coming don't want to waste the test.