My Neuro thought MG at first with me because my symptoms were mainly visual. Turned out to be MS.
Here is a link to a good article about diagnosing MS......
http://www.msfocus.org/diagnose-multiple-sclerosis.aspx.
Waiting for a diagnosis is the hardest part. You're welcome to hang out with us here at the MS forum and The Stumble Inn.
Let us know how the MRI went.