Hi I know your post is over a year old but from reading it I'm sure you might still appreciate a comment. I'm 17 and I've suffered from bouts of depression from a very young age, I attempted suicide earlier in the year; that was a real rock bottom point for me. Reading your post is like reading something about me. I completely understand how you feel! It's awful; deep down I know there's the person that I really am, but I can't get to her because there's this thing in my head that just affects every thought I have and everything I do. My Dad is clinically depressed and so "growing up with depression" has multiple meanings for me! He often says it's like having asthma (much like the tumor comment^) you'll never get rid of it, but it doesn't have to kill you or ruin your life. We just have to learn new coping mechanisms and try to find a way through. You're older than me so if anything I'm sure I know even less than you, I've only been medicated and had therapy for a year so far; but I'd just like you to know that even though we may be on opposite sides of the earth and we don't know each other, I know what you're going through and I have all the sympathy in the world for you! Please don't give up on things and let depression take away your life. You deserve to be happy. We all do.
Many people with depression go thru it in a manner similiar to what you are experiencing.
You're doctor should start to consider that you may need to remain on a 'maintenance dose' of medication all the time to help prevent the relapses. It's a lot better then going thru the constant swings and dealing with the physical effects time and time again.
I see many depressive disorders as long term ailments that can be successfully treated and frequently wax and wane throughout our lifetimes.
I tend to view depression as a tumour, one that cannot be operated on to completely remove, but can shrink and, if monitored and properly cared for, stay small. When you ignore the tumour it begins to grow again, and before you know it you've got a giant brain lump that you have to once again fight to shrink back down.
In our case, even once the depression has cleared we need to keep our new coping skills, practise positive lifestyles, and check in every now and then to make sure we don't feel a growth forming. The biggest mistake one can make with this mental tumour is thinking that it's gone for good, as when they do that they typically begin slowly sliding backward into old routines and ways of thinking.
This doesn't mean you will be unhappy for the rest of your life, or that you will be fighting a constant upward battle until the end of time. The struggle to maintain a life without depression will lessen, and the things you learn through therapy and/or self-help books will become more natural. What's left is maintenance and the occasional taking of your mental pulse, but beyond that your life can be as "normal" as any other.
It sounds like you're at a place right now where you need to figure out when to start taking your pulse - that perhaps this wasn't covered in your therapy. I would suggest bringing up post-depression maintenance with a therapist to see if they can help you find where you need to focus on in your own life and if/when you need to do those checks more often.