Originally Posted by
atomic sagebrush
This is actually totally normal. At about 7ish DPO your body releases a big burst of estrogen that helps maintain your uterine lining another several days to allow a potential pregnancy to get a good start. This can register as a temp dip between 5-8 DPO. Some call it an implantation dip and while it's actually not directly associated with implantation itself, it has been found by FF that on charts where there is a nice dip, they are more likely to end with BFP. Good luck!