Because someone who speaks quietly and only when they have something to say, can command greater attention than the loudest, most vocal person in the room.
Jot down kind words others say about you and keep them in a your wallet or handbag. Pick out a few whenever your inner critic needs a sharp rebuff.
Stop treating yourself inhumanely. You’ve punished yourself way beyond what is just for any perceived or real crimes you may have committed by forever berating yourself.