Wierd spotting...please help...

Ashley • 40, TTC #2...22 years later...lol
Im 37 and have been TTC for almosf 2 years now. AF is supposed to show in 4 days but I have been spotting for 6 days now (normal AF is only 3 days). No cramping but my boobs are sore and the rest of my body aches. Has anyone else experienced this? Any insight would be helpful. Thanks in advance.