Sorry to hear about your situation, being a student myself I know how hard it is to see school pass by.

Being active throughout the day is a fine balance between doing and over doing. Switching between low and highly demanding cognitive tasks is one of the coping mechanisms that can make it easier to get through the day.

Going for a walk in a quiet neighborhood or in a park is a good way to let the brain relax. Same goes for swimming and other very light aerobic exercises. Remember not to let your body waste away, while sitting in front of the TV
Remember the keyword here is light aerobic exercise.

I spend 6 month lying in a bed after my head injury and it cost me a lot of muscle mass and I also had two shoulder injuries by spending too much time lying on my side, so I would not recommend this.

Reading books are also a good solution for some, although it depends on the type of injury. Talking on the phone, listening to audio books or the radio are also recommendable.

Try keeping stress to a minimum and make sure to have a good diet as well.

Nuts, berries and fish are especially good for the brain. I usually snack on walnuts, raisins or almonds instead of candy.

Some people have problems with their eyesight after a head injury, especially those who hit the back of their heads. I had a friend who went 3 years with PCS symptoms until she was diagnosed with post concussion vision problem. An optometrist can check that out for you, if you don't feel like it is improving.

-Glasshead