Yorkiegirl I am just in from a work related meeting ( the things I do for a night out!) and can't really add much to the advice so far except before going to the dental hospital phone them to check they will see you as not all dental hospitals operate emergency "drop in" clinics anymore.You do need to see a dentist. There are so many types of pain and several reasons for pain that it is hard enought to diagnose sometimes even with the patient (and their teeth!) in the chair.
I am horrified that you have to see a dentist you don't like because of lack of dentists in the area. Are there no other dentists locally that are recommended by friends?
In the short term you could try getting some colgate fluorigard mouthwash from the chemist . (I don't work for colgate or have any interest in them). Use as directed.It may help calm the sensitivity. If it is just extreme sensitivity (to hot and cold)this may knock it on the head.
good luck.