I have been using ovulation tests and had a positive on the 2nd (day 13). I had stomach cramps on the 11th (9dpo) I did a hpt on the 13th (11dpo) and got a BFN. I was due on on the 16th. I am regular as clockwork. I have still had no AF. I have no cervical mucus. I did a test today and got another BFN. What's going on?