Safina,

Welcome to NeuroTalk. You have asked a very common question. There are no standard answers. Every brain injury is different. I suggest you try some studying as if you are preparing for your last semester finals. Nothing extreme, late night etc. In fact, late night cramming for exams is proven to be a waste of time if not detrimental to exam performance for a healthy brain.

Keep in mind that over stimulating your brain may cause a delayed relapse.
Plus, feeling better for a week is not much of an indicator of recovery.

Can you return to a light schedule or is there a standard course load that is expected? Can you do any of your courses online?

Only you can tell if you are pushing too hard.

What kind of grad program are you working on?
Does it require lots of memorization of facts and formulas or such?