Welcome to the forum.

I don't have the answer to your questions but I think you need to be examined by a doctor ASAP. If nothing else, at least it can be officially in your medical history. Until you can see one you should keep a note of all your symptoms as they present themselves.

Sorry that happened to you, sounds very traumatising. I was planning on studying astrophysics before my accident. I'm hopeful that I will still be able to with time and recovery. I find that my creative side has suffered the most, as opposed to my methodical/logical thinking which is required in science. But currently I am unable to follow equations and get very sleepy and headachey after doing a couple. That said, I wouldn't worry about it affecting your studies at this stage because everybody is different. I was unconscious momentarily and my symptoms developed quite severely within hours after the accident. But I really do think you should see a doctor as soon as you can.