18 DPO and 4days late for AF

Steph

I'm 18DPO and 4days late for AF. I wiped yesterday and has some very very light pink but nothing on my pad. I woke up this morning and same thing. I have very light "cramping", my breasts feel heavy, I have headaches, a stuffy nose, lots of urination and I'm tired.

I took a test Wednesday and was a BFN. Any ideas??