The MRI is a piece of cake. I had one of my brain and cervical spine, with and without contrast (with constrast they put a small injection of fluid into your arm, completely painless). It took about an hour and sometimes they give you little headphones to listen to music. My 12 year old daughter had to have one a year ago for a knee injury and she did fine also so don't worry. My 15 year old just had one of her brain this summer (all was fine thank goodness) and she actually fell asleep in the machine.
As Mark indicated, if they find something, you will hear back very quickly. When my sister-in-law had one this summer, she got a call in literally 4 hours from the time of her test because they found something (a benign tumor in her spine. She was operated on and is now fine and getting ready to return to work as a teacher.
I had mine on a Sunday morning in July and didn't hear anything started to worry (as Mark said). I called my neuro's office by that following Tuesday, they got back to me Wednesday morning and said all was normal except a slightly bulging disk between c6 and c7 which is around the area where we all hunch over slightly when when on the computer and I am a two pillow sleeper so my head is always tilted up slightly when I sleep. They told me it was very mild and is very commom, as most people never even know they have a slight one.
Try the meditation tactic, especially if they give you music to listen to.
Relax, everything will be fine. Let us know how things go.