Hi Jenn,
Welcome to the forum. You know we cannot diagnose you over the internet but we can offer our opinions based on our our personal past experiences. That being said , it sounds like you have a lot of neurological symptoms in addition to the optic neuritis which would make one think of MS but there are a lot of MS mimics that could be the cause of some of your symptoms.
Our Health Pages located at the top of the page in the upper right hand corner, next to the yellow icon contain a wealth of information on a variety of subjects. One of those subjects is MS mimics.
Below is the link to the MS mimics page;
http://www.medhelp.org/health_pages/Multiple-Sclerosis/MS-Mimics---Part-I/show/375?cid=36
Your doc may be correct with the diagnosis of probable MS but he is wise not to write that diagnosis unless he is positive and until you have insurance.
We are here if you have any more questions. sorry we cannot give you a direct answer but we are patients, just like you, except with more experience with MS.
Take care and keep us updated,
Ren