Tilt Table Test Tomorrow

I have an appointment with the cardiologist's office tomorrow, where they are going to perform a TTT... that's short for Tilt Table Test. I decided to "google" it to see what I was in for... hmmm it's going to be interesting to say the least. I am very frustrated with the doctors guessing what's going on with me. Here's a brief recap (as brief as possible considering this has been going on for months now): I went to the doctor with lightheadedness/dizziness and a pressure between my ears. I could prevent fainting by taking slow deep breaths and by sitting/laying down. The internist referred me to an ENT, who said nothing was wrong with my ears (although she sent me for inner ear tests which came back clear) and ordered an MRI. When the MRI came back with a few "white spots", she suspected MS and sent me to a neurologist. The neurologist reviewed the MRI and said, no it's not MS. He did a few autoimmune tests and sent me to a Rhumatologist (because of a positive ANA test). The Rhumatologist did more tests and ruled out autoimmune disorders. She sent me back to the neurologist who did a spinal tap (which sent me to out-patient surgery for a blood patch). He further confirmed no MS (no meningitis, no West Nile, no Lupus) with the spinal fluid tests, but couldn't find anything else either. While in his office, his nurse checked my blood pressure and found it different when I was laying from when I was seated. Now he's sending me to the cardiologist for this tilt table test. I think that some of the most frustrating things are: never feeling "well", exhaustion (although the doctor found Vit B-12 deficiency so I'm on tablets to help with that), fear of fainting in public, waiting between tests for results, and second guessing if stress or hypochondria is getting to me. I'm only 34 years old... I don't have time to be "sick". I'll keep everyone posted on results.