Trauma that results in an individual struggling with PTSD can create a significant challenge in one's ability to "trust" not only others but "self" as well.

The brain experiences a chemical surge during a traumatic event, often the individual "freezes" when they experience a traumatic event that catches them completely off guard. So basically that person is in a state where they experience or witness something that happens where they literally have no control or ability to stop or prevent that trauma.

It really takes "time" to slowly move forward in one's life where that state of powerlessness during a trauma is slowly overcome. First of all, the PTSD itself takes time to develop and it develops in stages, then the "healing" and recovery takes time a patience to where someone slowly learns how to live and regain themselves through patience and therapy to do so. This feeling of "Nothingness" is part of the PTSD itself and it requires one to be very patient with self as you "slowly" begin to trust and gradually move on with your ability to trust in yourself to resume living your life.

Everyone is a little different depending on their history and the trauma or traumas they may have experienced.