I've been in a deep deep depression many times, so i know exactly what your talking about man, and i'm still pretty young. All my life I have suffered from depression which eventually manifested into Bipolar in my late teens.
But theres only so much that meds can do for you. Mental illness runs in the family and my dad taught me that you just have to try as hard as you can to tough it out and force yourself to look at the bright side. You have to look on the otherside of the fence.
A coping mechanism my dad taught me was to look at other people in the world, compare your social/economic standpoint to the most unfortunate people in the world. I always do this in my head when I feel really depressed and have gone through some shit. I think about how horribly bad some people around the world have it.. people working in sweatshops in asia. young women in the Philippenes brought up as sex slaves when they were still children and at that age we were still riding bikes not a care in the world, and a sex slave is all the will ever be and for the majority of them there is no escape.. until death takes them into the void. (my step mom was from the philippenes)
It's a great way to get a more positive mind state for the present. You have it so good compared to a lot of people in this world. You have people that love you and care about you, and you love them. And give yourself more credit, you made it this far in life, and we only get one life, try to spend it with a more positive outlook. Realize that one day we will all pass into the void, and nothing we do will be remembered after we all fade out of existence, so what matters is the present, and the close people to you that love you
(I kicked all SSRI's/anti-depressants that i was on, cold turkey, in 10th grade and have strictly dealt with my mental issues my own way since)