No AF and no BFP..

Alyssa
Currently 4 days late and having some sharp pains in my lower belly. AF was due Thurs 12/17 and today is 12/21. Keep getting negative pregnancy tests. Never been late before. Been TTC for 8 months. Has this happened to anyone else? Do you know why you were late? Or anyone else get negatives and end up being pregnant? How long till you got your positive ? Or do you know why you got the negatives?? I'm so confused. Praying for a Christmas miracle over here :/ ♡♡♡