Just as every brain injury is different, I think each return to work plan should also be unique.
Within a gradual return to work (each week you should monitor symptoms, if they worsen return to previous week), I found in this forum the following return to work accommodation "guidelines" for brain injury:
http://askjan.org/media/brai.htm
Again, this is in the U.S. and for the ADA (Americans with Disabilities Act), but it provides some information.
The anxiety must be overwhelming--sending you lots of light!