Welcome Limitless,
I agree with the other posters, take it easy and defer to good medical advice on exercise.
Frankly, it is too soon after your injury to really know how your recovery is going. A clean CT scan means little: it isn't subtle enough to detect more than bleeds. Not to scare you, but many of us here were told we'd be over our little concussions in eight weeks only to later discover that we'd sustained diffuse axonal injuries or would would suffer from PCS for years.
The more we learn about concussion (and sadly troops injured by roadside bombs in Iraq and Afghanistan are providing lots of research subjects), the more it becomes clear that there is no such thing as a minor brain injury.
At this stage, if an activity aggravates your symptoms, your battered brain is begging you to stop doing it. Would you run on a broken leg? I was a serious athlete before my TBI so I know how frustrating enforced coach potatoness can be. However, you don't want to do anything that slows or limits your ultimate recovery.
In the meantime, be attentive to your symptoms. If they persist, if you notice cognitive deficits or if you (or others) notice personality changes, don't be afraid to push your doctor for more specialized testing.
Good Luck and Patience