Brain feels blank, should I see neurologist?

Hello,

So I have had this symptom from November 2015, I think. I was slightly depressed at the time (work problem), and begun to lose sleep time. The depression got better (at least I think so), but then my brain felt blank, until today.

If I'm to describe it, it's the back portion (back of the skull) of my brain that feels empty. I don't know how I can feel it, but I just do. The front portion is working, but not the back portion, at least not 100%. The best analogy I can think of (in my limited thinking ability), is like a horse ready to race, but no jockey riding on it, to tell it what to do, if that makes any sense.

I can listen to somebody talking, but feels like very distant. When he stopped talking, and waiting for my feedback, I couldn't really process what he just said. I can remember his words, just hard to process it. Most of the times, I know what I have to do, but couldn't think of the ways to do it. I have become dumb, to simplify it. It's affecting my job, obviously. 

I can sleep to max 8 hours, but wakes up feeling more tired as if I got no sleep at all. My body in general feels fatigued, but no pains or sores. In the beginning I intended to 'ride it off', thinking it will pass eventually, but it's been months now. 

Searched the internet a bit, is this fibromyalgia and/or chronic fatigue syndrome? What doctor should I go see, a neurologist? 

Thank you in advance.