I think things could really get lot better if you could just get some professional treatment. I know you've been reluctant to talk to gp, take medication, or see a therapist.
I hope you could either overcome those fears, or at least go see an acupuncturist if that would be an easier for you. Acmac.net has list of community-style acupuncture clinics in the UK.
A meditation practice might really help you too.
Trying to kill yourself would be a terrible tragedy if you could simply get better with treatment.