I suggest that between now and the beginning of classes, you do some intense study and reading as if you are cramming for finals. You need to determine how much stress your brain will handle. It is problematic to find your overload point after the last drop date. It can lead to some horrific grades.

I started second semester doing great. Even was doing OK after my high fever when I dropped Zoo101 ( I missed an important field trip). Then course work started to get intense and I collapsed. I got an A- in physics 1a and next semester got a C- in Physics 1b. I had always aced hard sciences.

Go to Lumosity and Posit Science and do as many free brain training programs as possible. Find your limits. Then you can be prepared to work within them.

Every concussion has residual problems. They just do not show up until the stress load hits critical mass. Some people can live a long life before hitting the critical mass stress load. Academic course work can often be a stress overload.