Hi Paul,
I got myself a therapist when I had left the Borg. Depression had got so bad I was going to kill myself, she saved my life. Seek help, you can get it on the NHS, insist on a therapist, pills are not the thing.( Temporary use is O.K.,they are not a cure).
My Therapist showed me how to drag myself up from the depths I was in, but even better, she showed me how not to sink in to any kind of depression ! I am so glad she did. My life right now, I can assure you, is more shit than yours is, but I can keep depression away, and I can even laugh, smile and feel happiness to a degree !
All the best Buddy, get a Therapist !