Hi Sam,
Welcome to the forum. A lot of us have been through similar experiences and know how hard this is. It can feel as though you're losing your life and no one understands. It will get easier.
The first thing I would like to say is that things are going to be okay even though they are going to be different for now. I have had to accept a lot of things being different. But I still have to say "accept, accept, accept" to myself over and over sometimes, about things that are changing.
It sounds like you were on a pretty good recovery plan, but that you were forced to return to school before you were ready. I know you, your parents, and your teachers are all worrying about your grades and life. What I am learning, especially with support on this forum, is that we have to address what is happening with our health right now, before we can start planning for next year.
So here are some thoughts, some of which have already been mentioned:
1. Your parents need to advocate for you between the doctor and the school. You should not be pushing so hard at school that you develop symptoms to the point of suffering or you will not get better. The doctors should have a detailed "Return to School" type of plan that the school must follow (something similar to
http://www.chop.edu/pages/return-lea...n#.VRlOj0Kpn48). Try not to worry about missed time. Have your parents talk with the doctor and the school about any options regarding medical accommodations. Half days, tutor, half workload, limited makeup work, no tests or take home tests, at most, I would think.
2. We all wish it were different - boy, do we - but there is no magic cure but rest. You must rest. You are not "lazy" at home. Don't give yourself that negative label. This is recovery. It is your job to rest. If you feel like you need to do something, try listening to audiobooks rather than playing video games - or there are other posts on here that have good ideas of restful things to do.
3. Maybe your parents could talk with your siblings about being a little more supportive. Everyone can be more educated about brain injury and what kind of environment can help you recover.
4. Depression is a common effect of concussions. Don't be embarrassed about talking about it. It's not just a symptom, but it can also continue because of stress and life changes. This is a big ongoing problem for me. I see a therapist regularly and I remind myself that yeah, this is hard and sucks and I feel bad and it's okay to be where I am and tomorrow is a new day.
Hang in there.
Be well
Julie