Doing academic study when ill is a real struggle. I recently did a master's in applied linguistics, and went hypo twice during that time: once was when first diagnosed, and then a year later because my previous GP made a hash of things. I found everything so much more difficult when ill - it was like thinking through fog, and like you said, concentration, memory, planning, ability to read, and everything goes. My essay results paralleled my health at the time so exactly, it could have been used as a diagnostic tool LOL! I've got better now on the right thyroid replacement.
As others have said, getting your free T3 checked would be good. Mine was very low even with an ok TSH and free T4. I now take a combination of T4 and T3, which works a lot better for me than only T4.
Good luck, and please keep us updated