Root canal

[Lauren miller]

I had a deep filling done 2 weeks past Monday. From there I developed problems so ended up needing to have root canal treatment. Had it performed last Saturday then ended up at the out of ours on the Sunday as the pain was really bad. They prescribed me antibiotics amoxicillin 7 day course 500 mg 1 3x a day. However didn't notice much improvement at all. Went back to the dentist the Tuesday and he reopened the tooth and recleaned it which was excruciating. Even with a lot of anaesthetic I could still feel horrible pain. He says it was quite infected still. Ended up back at the dentist the next day which was the Wednesday as was still in agony. The dentist I saw done the exact same thing and mentioned it was getting better. Then on the Thursday I was back and they changed my antibiotics to co amoxiclav 500/125mg 1 3 x a day for 7 days. It is now day 4 on the antibiotics and the tooth is sore again. It felt better yesterday and was managing with less pain relief but today it's quite sore again. Not anywhere near as severe as it was but still sore. Suppose my question is does any one know what this could be and what's my next best course of action? Stressing majorly as I'm afraid of the dentist as it is
Many thanks

 

[calcium48]

would help if you mentioned which tooth it is.
Did the dentist have a microscope to do the root canal?
Was it done on the NHS?
How much was the root canal cost?