If you believe you may have MS or are worried that what you are experiencing may be MS, then your first port of call should be to tell your local Dr (GP in the UK). They can refer you to an expert or specialist Dr who can further investigate your symptoms.
This will also give you an opportunity to ask questions and if required, the specialist is in a position to make a decision on any tests that may be needed.
The process may be frustrating, because we just want a quick yes or no, but due to the complicated nature of MS there have to be certain tests done, patterns noticed and symptoms experienced, before a diagnosis can be made. The criteria are called, "The McDonald Criteria".
This stage is very important, as it will give you peace of mind! One way or another it will tell you what is going on in your body. And, if it does turn out to be MS, at least you know and are not left in limbo.