seriously confused

Amanda
So I am currently on metformin which has regulated my cycles significantly over the last 6 months.  I am currently 2 days late and have been expericing some normal symptoms and some out of the ordinary for me.  I have had significantly heavy CM close to EWCM on days 5-9 post ovulation. And I have confirmed ovulation.  I have also had headaches and strange cramping/pelvic pain companied with slight back pain.  I am going on 13dpo and still getting negative tests.  I am sure my period is just late... but has anyone else had these symptoms and then find out they were pregnant several days after your missed period?
Thanks in advance :) we've been TTC for 1.5 years and I'm used to not over analyzing or at least trying not to! This month is different tho for some reason!