Hey! Welcome to the world of temping! Your temps should stay above your coverline, but other than that they can be all over the place. 6/7dpo is a bit early for it to be dropping in relation to AF coming, so I wouldn't worry there. There are plenty of reasons for a drop around that time such as, but not limited to....
A) Implantation dip
B) Second estrogen surge dip (often mistaken for an implantation dip)
C) Change in sleeping environment
D) No real reason at all
Unless you're closer to 11dpo, a lower than usual temp is nothing to blink at. Hope that helps! FXed!