No AF in sight but 4 BFNs

Jamie
I am now on a 45 day cycle (my norm is 29-31).  I have had mild to moderate cramping for about 10 days on and off.  I have had sore breasts for the last 2 days.  I have tested on 9/3/15 , 9/9/15 , 9/10/15 , and 9/12/15 all with FMU.   I really thought I was going to get a positive result because this has never happened before.... I am new to the area so still yet to get a doctor also but know I should probably go.... I just want to know what the heck is up?!?