My basal keeps dropping, 13-14 dpo

Dyani
Okay, so I normally spot before a period, no spotting yet my last period was June 3rd, I have normal 30-31 day cycles. This is my first month temping so I'm new to the whole thing, my temp has been going down for 2 days about .1 a day do you guys think af is coming or should it be more significant?