For 12 years I thought I was crazy and that I must have a mental disorder. All my MRI's came out clean too. Then one day AFTER some of my worst symptoms were getting much better, my doc ran another MRI and low and behold many many lesions showed up. I was relieved NOT to be crazy. Just keep on trying to find whats going on. Let your doc know how frustrated you are and how you feel.....these types of things can get us so far down that depression sets in. If your doc says its not MS, then you have to ask, "well, then what is it?" Thats a fair question and keep fighting for the answer. Big hugs to you.