Hi Shecould and welcome to SR.
Many people with an addiction (and you seem to have recognised that you have one as your behaviour around cocaine is no longer recreational use) find it difficult to quit and
stay quit on their own.
I really would suggest you think about getting some support. Cocaine Anonymou or Narcotics Anonymous would be a good place to start. There are plenty of meetings in London.
Welcome to Cocaine Anonymous UK Narcotics Anonymous - Meetings
Keep in touch