Hello MissChainChomp and Welcome to NeuroTalk.
I am sorry your dad has MS

I can understand why you are probably worried about having MS.
Have you talked to your Primary Care Physician about your symptoms and concerns? Have you been to an Optometrist or Opthamologist in regards to your vision problems (double vision)? Your dad would be a good resource for information about the diagnostic process.
If you are prone to getting the flu it would probably be a good idea to get a flu vaccine each year
MS is a diagnosis of exclusion, other reasons for a persons symptoms must be ruled out before MS can be considered. Blood tests are the first thing that needs to be done as this can rule in or out other causes for symptoms.
There is a criteria for diagnosing MS...The McDonald Criteria. Although the Lumbar Puncture can be helpful for some in recieving a MS diagnosis it is not always necessary. There is no single test, by it's self, that will produce a diagnosis of MS.
This link to The National Multiple Sclerosis Society will give you some information about diagnosing MS:
http://www.nationalmssociety.org/abo...-ms/index.aspx
I do hope your symptoms are not a result of MS and can be easily resolved