DPO??

Cheryl
How do I tell how many DPO I am? I never got a peak with the clear blue digital ovulation test. I had high (flashing smiley) from 6-13 August, then I ran out of tests. AF is actually due today, but I deleted it as it hasn't shown. 
I have no idea how to read my CM, etc. It's currently creamy. Cervix is medium to high and closing.