My daughter had a very mild concussion this spring. No loss of consciousness or dizziness. We didn't even think she had a concussion until she woke up feeling woozy the next morning. She passed the neuro exam, but her symptoms were enough for it to be labelled a concussion by the pediatrician. Protocal was that she couldn't return to sports or anything else that might jar her brain until one week after the final symptom. She ended up missing a week and a half because she shook her head hard one day in class and then felt dizzy.

More severe concussions are treated by total rest. No visual stimulation, especially blue light. No TV, dark room, etc. So a return to fully normal is unlikely after such a short time.