I can actually relate to how you feel. I don't know about feeling like this all of the time, but for the good majority of the time I do. From what I've researched on my own, it could be a condition called 'brain fog'.
Here is an extensive article about the different types of brain fog:
http://www.drlwilson.com/articles/brain_fog.htmI don't exactly think you have an anxiety condition. If you're not experienced panic attacks or troubled thoughts, etc. If you were, then I'd assume it would be something like depersonalization, a common foe of those stricken with anxieties.
Let me know what your psychiatrist says. I'm interested to know what it is exactly.