MS can be a very difficult disease to diagnose. Typically, a person with MS will have lesions visible on MRI, but not always. Typically, a person with MS will have abnormalities in their spinal fluid, but not always. Typically, a person with MS will have a history of symptoms that demonstrate a pattern consistent with MS, but not always. It is this unpredictability that makes the process so challenging. There is no single test, and no specific combination of tests, that will always correctly diagnose multiple sclerosis.
When tests are inconclusive and the doctor doesn't have answers for you, it's easy to wonder whether the symptoms you are experiencing are "all in your head." At times, well-meaning medical professionals may even foster that idea by suggesting what you are experiencing might be "just stress." While we can all benefit from reducing our stress, MS experts know that the disease can often take years to diagnose, as can several other autoimmune diseases with similar symptoms. If you continue to experience the problems that led to you seeking a diagnosis, don't give up on trying to find answers.
It can be helpful to seek a second opinion from a doctor who specializes in the diagnosis and treatment of multiple sclerosis. These experts may recognize signs that may not be apparent to others. However, sometimes only time will truly tell if a person has MS. Tests may need to be repeated after a specified period of time, or when new symptoms appear.
Today, many doctors prefer to treat cases of "probable MS" as though their diagnosis was certain. Early treatment can slow the progress of the disease and potentially prevent relapses. If your doctor cannot provide a definitive diagnosis, discuss whether the evidence is strong enough to merit starting treatment.
Sadly, some individuals remain in limbo for years, suffering from symptoms but unable to get diagnosed. Don't let the lack of a diagnosis stop you from seeking support. Consider joining a support group for the chronically ill, or specifically for people with MS. Not having a diagnosis should not, and can not, stop you from relating to those with MS or sharing and receiving support.