Lui,

What are the doctors saying?

Have you had any exams of your neck, specifically your upper neck? It can get injured and cause inflammation that can slow the blood flow through the vertebral arteries. The brain still gets blood from the carotid arteries but not as much in total.

A concussion can also mess up hormones of all types. An under-production of Thyroid hormone can cause weakness/fatigue.

It probably will take some digging by a doctor or two to figure this out. Does your school have an athletic trainer? If so, maybe you can get a referral to a better doctor. Were you playing on the school team or was it just recreational/intramural? Schools usually provide good care for students injured during a school team practice or game.

As you say, this risks getting sent home. Try to not act anxious. It can give them a reason to send you home. If you can show patience and discipline, they will be more likely to give you a chance.

Are you continuing to play basketball? Are you active in social groups? Are the studies challenging?

Please be honest so we can give you valid comments.

My best to you.