I used to feel the same, I have always avoided the dentist. Then at christmas, when the dentist was on holiday, I got an abcess on my wisdom tooth. it was my own fault, I knew I needed to do something about that tooth, most of it had broken off, but I just buried my head in the sand.
It was the worst pain of my life, far worse than childbirth, seriously. When I finally got to the dentist, she said she'd have to take it out. I was terrified. I closed my eyes while she injected the local anaesthetic, it was uncomfortable, but only lasted 15 seconds (I was counting). We chatted for a few minutes, then I took a deep breath, closed my eyes and visualised myself on a sunny mountainside in tuscany. I was aware of a bit of rooting around, no pain whatsoever. 30 seconds later, she said "all done". I couldn't believe it was out. Since then I've been back for fillings ( I had never had a filling, it was so much easier than I thought)
I need to go to an oral surgeon to have 2 more wisdom teeth removed, my dentist has recommended one who she says is very gentle and careful. I asked about having it done under general, but she says it's better to be awake, that I could have a valium before if I feel I need one.
What I would recommend is asking everyone you know what their dentist is like, until you find a kind understanding dentist, and tell them exactly how you feel, about how stressed, sick, etc the thought of the treatment makes you feel. An experienced dentist will be used to dealing with anxious patients, and will help you through it all.
Overcoming my fear of the dentist has really empowered me, I feel much better about myself, that I was able to deal with the experience.
And going to the dentist is no-where near as bad as an abcess on your tooth