Hi Andy,
Unlike with other autoimmune, they have yet to discover a genetic factor in regard to MS. You will hear about families that have a history of MS in them, but more commonly you will hear more about families with different autoimmune diseases spread around. What I would suggest is to go ahead and make that appointment and be seen. There are a lot of illnesses that have similar symptoms to MS, and be prepared for lots of testing as MS is a diagnosis of exclusion rather than testing for that particular illness off the bat.
Its not uncommon to have the feeling of will they take me seriously. Be proactive with your own health care, there are those out there who will listen to you. Let us know how you are doing and I wish you the best in your search for answers.
Kimber