I have Schizotypal and I have foggy days and super sharp days. I don't think it is directly related to the Schizotypal since that is the description of a set of traits in your personality, and not an affliction like Bipolar or Depression.
I think my diet and the depressive part of my Bipolar type II can cause me to get foggy mentally.
But don't let any diagnosis hold you back. There are so many highly successful people that have all kinds of brain cooties. You can do anything you want to do.