"Blank staring" is described in the literature on post concussion syndrome (PCS) and may be associated with the "immobility response" that is part of the "fear, flight or fight" reaction to danger. When overwhelmed, the nervous system, particularly the autonomic nervous system, shuts down as a last resort.
Also, blurred vision is a very common symptom of PCS as is sensitivity to light and sound. Yes, this is an indication that you need to rest, brain, body, or both.