Your not crazy marlene, nor is anybody here. PTSD symptoms are a huge learning curve, and just when you think you have lived it all, another symptom will throw something else your way. Anxiety is the factor behind hypervigilance, as Bec stated. The reason your hypervigilant is because your anxious. You narrowed it to travelling to and from work, and at work, hence the anxiety state. Your going to a place of constant exposure, during the exposure, then the trip home is like the rundown of the exposure for the day. You return home, your now "safe". Once that safety factor kicks in as such within your mind, anxiety levels decrease rapidly, hence hypervigilance also decreases. Its nothing more than a normal symptom of the real problem, trauma.