The brain is poorly understood, and no one can know the answer to that. But those are irrelevant questions to ask. You can't stress about what you should or shouldn't have done. That's in the past, and you can't do anything about it. All you should do is focus on your recovery.

See above. Although having an incident like that at 5 weeks is probably a lot better than at 2-3 weeks...

Some do, and some don't. There's a study on the topic, if you google a paper written by Carmen Hiploylee, "Longitudinal Study of Postconcussion Syndrome: Not Everyone Recovers". (I'd post a link, but it won't let me do that).

On the one hand, it's a little depressing, because it shows that a lot of people don't recover. But it also shows that three months is still very early in the recovery process, so you shouldn't let yourself get too stressed at this stage. You're also probably considerably younger than the average age of the study, so your odds are probably somewhat better.

Also, being "not recovered" doesn't necessarily mean your life is over. I think the flaw with a study like that is, what's the definition of recovery? Let's say you were super messed up for the first few weeks, and then a year later, you're mostly fine, except that your balance is still a bit off, you have some ongoing neck pain, and your a little bit more forgetful than you used to be. But you can do your job, and/or succeed at school. Does that fall into the bucket of recovered, or not recovered?

I think that's extremely common, especially in the first few weeks. I had some issues in the first 3-6 months, and now at 9.5 months, I think my cognitive issues are 90%+ resolved (though it's admittedly hard to say for sure, since I wasn't formally tested before and after) and my co-workers tell me that I seem fine in that regard. (I do have other issues, like fatigue, eye/neck pain, and still not being able to drive -- at least not on a highway).

I know a guy who could barely read/comprehend his emails in the first few weeks, and after a year or two, he said his cognitive ability returned to normal.

So don't let yourself get too stressed at this stage. You're a step ahead of most, by doing all the things you're doing. And again, your age should play to your advantage.