4 days late - still no af and bfn!?

Ashlyn • Ttc#1, married on 7/5/13, ttc since then.
Hi ladies! Any advice would be very beneficial! 
My husband and I have been ttc for 9 months. My cycles have gotten progressively longer. Three months ago my cycle was 33 days long. The past two months it's been 36 days long. I was supposed to start af last Friday( March, 21st) I have taken two tests, one last Friday and one this morning. I got bfn and have no signs of af. 
​I had a peak ovulation on March 3rd and lightly bled 6 dpo.
​Any thoughts of anyone's cycles getting progressively longer! It will be 39 days today and still no af, but getting bfn!