Let me tell you my experience with brain trauma and MRIs.
I had a normal MRI after having a crainiotomy. I experienced extreme fatigue, concentration/cognitive problems though. I finally went to a neurologist and asked to be tested. He started me on Amantadine, often prescribed for tramatic brain injury, and ordered neuropsychological evaluation. I had dramatic improvement on the medication and almost canceled testing, but I didn't. The testing determined that I now have a learning deficit. My neurologist said he was glad I didn't cancel the evaluation. I really got the idea that he thought I was just a neurotic mess until the testing reveled the damage. Of course if it was me being neurotic it would have been a lot more "fixable".
Have you seen a neurologist?