Hi shropshirelass,
Hope you are getting some relief, there's nothing I would add to what the others have said other than you have my sympathy. I have had x2 root canal treatments and New Years week ended up with an emergency appointment and given oral antibiotics for an infection in one of the treated areas, my regular dentist to follow me up with long term plan for this tooth. The pain is horrendous. Let us know how you get on. x