Well, as Karma predicted, my MRI was normal.
I have to keep a symptom diary for a week and then go back. What I really want to do, and what I think I will do, is go in if I happen to have a 'bad' day between now and then. By bad, I mean really fatigued, shaky, numb, weak all the crap I've been dealing with for the past months/years. I want my doc to see my when I'm like that rather than on a 'good' day....I can try and describe my symptoms to him all I want to, but I think him seeing it will be much more helpful.
So, whilst I now know I don't have a tumor, I'm still left wondering just what the hell IS going on. I have my suspicions...but for now I'm going to just soldier on and not worry about it.
I still wish I hadn't gone to the doctor though.