At 9 and 10dpo I got a vvfl on frer. Very faint, yet definitely there. Today I was excited to test again and see a slightly darker line, however, it was a bfn! Frustrated, I took the digital test that had came in the same pack and it was invalid (the clock symbol showed up but didn't blink and stayed constant for over 10 min after which I tried taking it apart and it flashed through all the symbols and stopped with a "yes+" plus the clock).