Hi SWLover,
WAP in Balham has a good low cost service:
http://www.wandsworthap.co.uk/ and an experienced psychotherapist would assess your needs in the first instance.
I am a therapist (BACP registered
http://www.bacp.co.uk/) in south west London who posts on here when I see someone needing some help.
If you want an off the record chat about what to do, who to contact etc. send me a a message. We could speak on the phone or email or Skype etc.
Good luck and well done for reaching out to this community.
David