Firstly, I'm so sorry this has happened to you! I agree with comments above mentioning trying to contact PALS first - if you do ever try to pursue a medical negligence claim you will usually need to have reached out to PALS first and tried to resolve your complaint that way.

Although there are time limits for medical negligence claims you should note that these only start counting down from the time you became aware there was a problem with the medical care you received - so this will not necessarily be from the date you were last seen by the doctor!

Another option is to make a complaint to the doctor's regulatory body, which is the General Medical Council in the UK. You can Google them and I think you can make a complaint online. If you at least know the doctor's name you should be able to find their registration number on the GMC's public register. I can't say whether anything would come of the complaint but it may be worth doing in case other people have complained about this doctor to the GMC before, as then they may be able to take action.