Perhaps the most important thing at this point is to give yourself lots and lots of rest. Do not exercise at all. Start spending a lot of time in quiet relaxation or meditation, or doing a hobby that does not require much mental or physical energy. If you try to continue to work and exercise, you will likely get worse.
Avoid alcohol, caffeine, and junk food, and try to eat as many whole foods as possible (see the "brain friendly nutrition" thread). Be sure you are getting vitamins B6, B12, folic acid, D, C, and Magnesium (I'm probably forgetting some...others will fill in).
Limit your exposure to highly stimulating environments and activities, including bright lights, loud noises, TV, movies, etc.
This is not easy, but it will be much harder if you try to live your "normal" life without giving yourself time to heal. There's a hard way and an extremely hard way; there is no easy way.
We are here to provide further guidance and emotional support as you go through the process of recovery. Take care and be strong.
Male, 36 years old, suffering from PCS after being rear-ended on 1/23/11. Was largely recovered before suffering a severe relapse in August of 2011, which was apparently caused by too much computer work.
Most persistent symptoms are light sensitivity, sound sensitivity, headaches, brain fog, dizziness, fatigue, and eye strain, all of which are easily induced by activity.
I also suffer from Obsessive-Compulsive Disorder (OCD), Chronic Fatigue Syndrome (CFS), and Major Depressive Disorder. I had all of these conditions before my brain injury, but the CFS and depression have been exacerbated by the injury.