I'm possibly getting dumber

I'm pretty sure that as I learn more and more of this bar stuff - or relearn as it is - I'm also becoming dumber. How can I say that? Because I find myself questioning the spelling of the simplest words. Do I mean week or weak? Meet or meat? They're, there, their or you're versus your. 

I think it's very possible that our brains can only hold so much knowledge.

And it's only week two. (Or is it too or to???)