A THIRD BFN.... Confused

What's up??? I got a 3rd BFN. I took one a week ago, one the night before last and one yesterday morning, thinking the hormone would be more concentrated so I could get a positive, but nope. What's up??? I'm 7 days late now, but still nothing. I don't feel any different. I've been irregular all my life but and since November of last year, I've been regular until now. I don't know if I'm pregnant or irregular again. But if I am, why did I regulate out for those few months? We used the fertility calendar also last month. Ideas?