Dont stress. Probably is just too early. I never got a Bfp before AF was due on any of my pregnancies, though some girls do. Im always too scared to test early in case I get either a false pos, or worse, a positive test followed by AF. Thats probably just me being overly paranoid or superstitious.
Whats the earliest youve ever tested? Some people seem to start at 6dpo. Isnt that WAY to early??