Faint line or false positive??

Hi all! AF is 6 days late (I have never been this late before!) I've taken a bunch of pregnancy tests and keep getting clear negatives. Except for the last 2 clearblue plus have shown very very faint lines (barely visible! My husband couldn't see anything but my friend could). My husband and I have not been TTC just yet but have been using the withdrawal method which we both know is a little risky. Anyway, it's driving me crazy because I've never been so late for AF and with my first child I got a BFP 5 days before AF was due. Is there still a chance I could be pregnant but not enough HCG yet? I am CD32 on a 26 day cycle...