Hi there....WOW, it sounds like you really had a pretty significant concussion there.
It is very important that you refrain from any activity that involves putting any extra stress on your brain.
My niece had a significant concussion from a soccer incident and wasn't even allowed to return to school for several months!!
They said that she couldn't use the computer, watch TV and do alot of things that work the brain too much which could keep the brain from healing properly.
A concussion is s severe bruising of the brain and you really should have gotten some specific DO's and DON'Ts upon discharge from the hospital.
I would think that you SHOULDN'T return to work until you go see your doctor.
I am pretty sure that ANYTHING that requires concentration and working the brain needs to very limited for a certain period of time or you risk developing what they call Post Concussion Syndrome which will entail a much longer healing of the brain.
You really need to rest and take this seriously.....your brain has been through a major trauma and needs to heal.
Hoping that you are doing well and that your GP gives you more answers although my niece was under the care of a neurologist who is better equipped to tell you what you need to do in order to best recuperate from your concussion.
IF you saw a neurologist in the hospital it may be a good idea to call him and ask him exactly what you need to do to properly recuperate from your concussion.
Good luck and keep us posted with how things go.