It sounds like you are disassociating paradox. That is your brain/mind trying to slow down and manage the stress and taking a break. PTSD tends to disrupt the subconscious mind where we are often on "auto drive" but don't realize it. When we experience a trauma we are ususally caught off guard, and that affects how we develop a comfort with our surroundings in our subconscious mind. That is also why a person with PTSD becomes a lot more sensitive to their surroundings, and have more anticipation anxiety because we experienced something that was a major threat to our sense of safety and that can affect us on a much deeper level then we realize.

Are you seeing a therapist?