I have also had longer bouts of depression triggered by various events. From the moment you wake til the moment you fall asleep, the feeling of everything being a huge bummer is constantly over you. It's not something you can just turn off even if you want to.
For me, I've been lucky to have good friends that I can hang out with to take my mind off it when it happens. The last time it happened, it ended when I had invited a couple friends over to play FIFA and had a blast. The next day I was fine and it felt amazing.
I guess what I can tell you from this is that you should never give up! Find something that gives you energy and happiness. It's never as bad as you think.