I was anxious and angry about this test, too. I can NOT sleep on my back. Period. And when you have all the stuff hooked up to you, the only option you have is to sleep on your back. I was annoyed that I would have to get up and go to work the following day after not getting a good night's rest.
I was also annoyed because I knew I didn't have sleep apnea. My fiance and my dad both have it, so I am very clear about the signs and symptoms.
I was not diagnosed with sleep apnea, amazingly, and was cleared for the surgery. I didn't sleep well that night, but at least it's over.
Good luck, and hang in there. This was my least favorite part of the process. Not because it was awful, but because I can be real mean if I don't get good sleep!