I need supportive advice on how to shake off this agonising depression?

I wont go into all of the details as to the root causes of the depression as there are many and they are complicated and varied. The advice I need is how can I eliminate the immense greif and dark sorrow I am feeling. It has crashed over me like a heavy black wave after a hugely tension filled Christmas period and then a suprise visit and contact from some people from my past. That has only aplified how deeply unhappy and lonley I am.

How do you ask for help? What help is it I am asking for? I am on anti depressants and in therapy but this almost feels beyond that. The will to continue on is blackening my every thought and seems like a better option then this agonising pain. It is pain I have lived with in a range of forms all my life and I am coming up to 30 and I dont think I can cope with more of it.

How do I hold onto sustained hope and joy? What words do I need to use to ask for help? What help do I need? How can internal pain be removed for long enough to go on with a good fulfilling life?