A neuro is a good person to see, they can do an MRI or CAT scan (I am guessing...I have been scanned all up and "down) and see if they can see anything "abnormal". Make sure you see a good one, one with some experience.

I know that depression can cause big changes in your brain...I have read some things I wrote from back when I was not depressed and I don't even think I sound like the same person. So don't be too scared yet (although I am not invalidating your feelings, I am sure it is a very awful feeling, just like you say). But see if you can find an answer by going this other neurology route first. Hugs to you, and I wish you the best.