From what you've said here, it sounds like you've been trying to rush back into your normal lifestyle, and that this has been slowing your progress. The urge to get back to "normal" life as quickly as possible is quite understandable, but it needs to be resisted if you are to to recover close to your pre-injury level. The more you try to rush back into schoolwork, being busy, etc., the more likely it is that you will have some permanent residual effects, or even have a bad relapse (read my signature at the bottom).

It's hard, but you need to be patient with yourself and give yourself lots of time to rest and take it easy. That might mean cutting back on schoolwork or taking a semester or two off. Your long-term health is far more important, and if you try to rush too quickly back into your previous lifestyle, you WILL have setbacks, you might have a SERIOUS relapse, and you will be at much greater risk of having long-term problems.

You can feel better for long periods of time--days and even weeks--and still be nowhere near full recovery. What you find is that your activity tolerance levels are lower; it takes much less exertion (physical or mental) to get symptoms popping up, and as Mark said, you often don't know you've overdone it until a day later. The more you can learn to recognize early warning signs of stressing out your injury, and the more you can take breaks as soon as those signs begin to appear, the better chance you will have of a strong recovery.

So again, please be PATIENT and do not rush your recovery. Avoid overstimulating environments (i.e. light and noise), avoid physical overexertion, try to get on a regular sleep schedule, avoid alcohol, eat well, take frequent breaks for meditation or lying down, and avoid trying to multitask. Hang in there. There's a difficult way through this and a REALLY difficult way...there is no easy way. The REALLY difficult way is trying to rush back into a normal lifestyle; the difficult way is taking it easy and taking very good care of yourself. There is no other way.