Confused

Ummu

So my AF are 2 days late today.. I tested 3 days before my AF due git a faint line and then 2 days before AF due got a super faint line again..yesterday I tested again as it is said that the HCG hormone almost doubles after 2 days so it shows a darker line but guess what? I got a BFN!!! Still no AF I just dont understand whats going on