I'm glad the dentist was so lovely, and that you let yourself cry. I don't remember the science now, but crying has a hormonal or chemical connection.
My husband had something similar happen with a back tooth - first a root canal, then a crown, and finally, so much tooth loss that a new crown couldn't be fitted so they pulled a tooth and put in an implant. Once the procedure was done, and he had healed, he had no problems with eating.
Echoing what so many people have said here: Letting the dentist (or any medical personnel, really) know that you have fear, or have had bad experiences in the past, can feel so much better than trying to hold back the emotions you're feeling and the reactions you're having. Of course, the healthcare provider then has to do their part and actually be supportive and helpful. I have a lot of anxiety around anything medical or healthcare related - a routine physical at the doctor or a basic dental cleaning exhausts me to the point where I have to nap for the rest of the day - and I've now made it a point to make sure *every* *single* *person* who works with me knows my history and that I have feelings about it.