Ovulated July 15th... Still no AF

I have been using clear blue ovulation kits and ovulated July 15th. Today puts me at 18-19 DPO. My husband and I did a lot of the BD during my fertile time. I have been having some cramps for the past 4-5 days so I keep thinking I am getting AF but nothing yet. I took a Test and go a BFN today. I don't know if I should move on and I chalk this up to a late period or hold out hope.