I hear you and know how your feel. I am exactly the same, though have only suffered for 3 years. Depression is a major symptom - However, I can tell you that there are things I have done which have *improved* this...
These are:
1) Do this program http://www.atlantadentist.com/TMJ_Program.html
I have been doing this for 6 weeks now, and though i'm not cured things have improved. I am continuing on this program for months to come, as my body has been under alot of stress so I know this can only help.
2) Get a splint (im guessing you already have one)
3) Go to a kinesiologist monthly or something that relaxes you!
4) Im currently waiting on my sample of Theraflex TMJ - i'll let you know how this goes!
5) Don't give up - i know it's hard, and you've had it longer than me so I completely understand !