ScardeyCat -- I was absolutely TERRIFIED before my first root canal. Was seconds away from a full-blown panic attack when I got to the office. I told the endodontist how terrified I was and my 'rules' (I didn't want to feel anything, I needing to be flat back in the chair for injections -- I had previously passed out from dental injections, and I absolutely, under no circumstances, could see any needles). He was so kind and said to me that he would work with me to do whatever I needed in order to get through it. I was so worried that I wouldn't be numb because my bottom back teeth are very difficult to numb -- prior to this RCT I had never been truly numb for dental work in that area of my mouth. For the RCT, I was more numb than I had ever been which provided a huge amount of comfort and, when I felt little twinges during the appointment, he gave me more anesthetic right away and I felt nothing after that. It was long (90 mins or so), but was not anywhere close to the nightmare I imagined. After the first one, having had such a positive experience, it was much easier to have the other 3 (even though they were all with different endodontists).
Best of luck to you!