Seems a bit "busy". It looks mostly like a simple clocked
comparator. I think you might benefir by breaking it up and
putting it back together once you understand that the
comparator core is working correctly (like, does the bit
you are sensing really provide the complementary D. /D
inputs, or are you using a mid-range static input for one
and just looking for gain, and if to do you have the Vref
properly positioned?).
A shorted inverter, where you release the short just before
attaching to the sense line, might be simpler and adequate
if you have a single ended bit signal. You can get more gain
from a series chain if you like.