Job,

What kind of physio are you doing ? It may be pushing you too hard and too fast. The injured brain is usually slow to recover if it does not recover spontaneously. Work injuries are tough because the goal to get the worker back to work as quickly as possible. This is often counter to the needs of the head injured person.

Whether you can return to your job is not the only question. You need to consider if it is safe for you to return to your job. Your brain has already demonstrated its inability to tolerate an injury. Find a new job and seeking job retraining is likely a wise choice. Just don't push yourself cognitively just now. You still need to heal.

My best to you.