Anxiety is a common symptom of PCS. Sleep issues are very common too, some folk sleep too much and feel rough others have trouble sleeping through a full 8 hours (me). Maybe some positive thinking techniques before you go to sleep would help. I used to listen to relaxing music, think about my holidays and when I couldn't reign my thoughts in I used to rebuild my car engine in my head (weird but it helped). I used to wake up fully awake and wired, it's only recently I wake up feeling sleepy like I used to do. Some say anxiety is just fear.