I have suffered with depression since I was 16 so 10+ yrs now.
There is treatment for it so you don't feel like this every day. I have my good days and bad days and for me my depression will likely never fully go away as it's clinical and seasonal.
There are exercises you can do to help, positive self-talk, therapy, meds to help with the symptoms. Exercise is a big plus, it gets your endorphines going that makes you happy.
Don't give up, I can live with mine, it isn't as bad as it used to be... usually something has to trigger it for me to feel really down.
I can function in my daily life, even if I feel low. It takes time... and you need to try and start to do things to make it better... I know it's hard to think of life going on daily with feeling the way that you do, but there are ways to help it. I used to be bed ridden and pretty much a hermit for a year, my depression got that bad, and now i'm completely different from that time.
Have you sought out therapy?
Looked into purchasing any self-help books on depression?