My first cavity

Tomorrow is going to be a big disappointment of a day!  8 AM tomorrow I will be getting my first cavity filled.  I can't believe it.  I have always been so proud of the fact that I didn't have any cavities.  Dentists have always praised my dental hygiene and I've always left my appointments smiling (mostly because I was excited to get the H out of their office). 
Two weeks ago I went in for my cleaning and films.  Lo and behold I had developed a nasty little cavity on a tooth waaay in the back of my mouth in a place that I don't think my toothbrush can even reach.  And tomorrow I am going to pay for it.
I'm so nervous, I don't think I'm even going to be able to sleep.  I have a bit of a phobia of the dentist.  It's been that way since I was little.  I can remember walking into the dentist and my knees would start to shake while waiting in the reception area.  Even the smell of the dentist office still makes my stomach hurt.
I know that you are never supposed to wish away time, but right now I am just so excited for it to be 5 PM tomorrow and for my dentist appointment and work day to be over.