Welcome to ThisIsMS. I believe that you will find a supportive community here. I had never heard of conversion disorder before, but I found a good article on it from the Mayo Clinic
. The way it reads, anyone with MS-like symptoms could be diagnosed with this.
There was one thing though, the article noted that conversion disorder symptoms often get better on their own. From what you describe, your symptoms are not and seem classic for MS relapses. However, I'm not a doctor so it would be probably be good for you to find a new doctor who's willing to look outside the box that others have put you in so you can find out what's really going on.