This looks like dissemination in space (symptoms in more than one location in the body) and dissemination in time (times when the symptoms were bad, and then they got better.)
They always say go look at the McDonald criteria, because that's what neurologists use when they diagnose people with MS. So I do, and I have a hard time understanding it, even with this well-written health page:
http://www.medhelp.org/health_pages/Multiple-Sclerosis/Diagnosing-MS---The-McDonald-Criteria-revised-2005/show/370?cid=36
The problem is that you have evidence on the neurological exam that you have a 'clinical lesion' meaning that there's something wrong, but we only know about it from your symptoms. Your MRIs have been clear both times (even though we don't know what the strength of the MRI was.) You're going to need MRI evidence that shows that you have damage there. It's very difficult to be diagnosed with MS with a clear MRI.
So the question becomes how to better diagnose you - do you need a stronger MRI? Do you need a different doctor, that specializes in a different disorder?
Shell had a good idea - going back to your regular doctor, and tell him about the problems you've been having, and whether the Xanax is helping. I would also find out what the strength was on the MRIs that you were given.
I had constant problems with my legs - my neurologist could see it. But when he scheduled me for a 1.5T of the spine, it didn't find anything. The open MRI (.7T!) was even worse. So every time I came back to the neuro's office, he'd tell me "You're fine! There's nothing wrong with you." Finally I found some 3T MRI machines in the area, and asked to be imaged on one of them. Lo and behold, there were lesions all up and down my spine - some in the upper thoracic cord, and a well-defined one at T10.
This is why I go on and on and on anon about a 3T MRI. It makes all the difference.