"Complain" here all you want- that's what this section is here for; and, if you still feel like you're just "complaining," then please, PLEASE pm me. Trust me, I know the feeling of, well, feeling like I'm complaining.
You're right, you need to live. Considering that God loves us enough to wake us up in the morning, He obviously has a reason for us living. Keep reminding yourself that. I made a small poster to put on the side of the dresser by my bed, it says: "Isaiah 40:2- 'He wakens me morning by morning.'" It reminds me first thing when I open my eyes that He has purpose for me, even if I don't have purpose for me.
How long have you been feeling like this?
First, I recommend that you seek professional help. It may seem like a last resort for some, but it's as plain and simple as going to a doctor's office when you are sick. The people there know how to heal you; they understand how people work, and how to help them through problems. They really do help
Your profile says that you work hard...do you rest hard? Have you ever taken some time just to do, well, nothing? Life gets so busy and hectic that sometimes it's necessary to take some time off; it's necessary to our health. Hey, even God took a day off. 8 hours of sleep and lots of water is also very very helpful.
I recommend looking at how you spend your time. How much time do you spend as a busy person? Could you lighten your load to feel better? Or are you just doing nothing, walking around aimlessly in life? I know the feeling, even though I cannot estimate your personal threshold of pain. If so, you should get a hobby...seriously. Find something, or just try things (not like, drugs, or anything like that, cuz that won't help) like writing, painting, music, something to consume your time and also give you a tangible reward to your time. Give your all in all you do, and you will never be unhappy with the outcome.
The most important thing: work on your relationship with God. Pray. Read the Bible. Let His Word become part of what you do, daily. Get post it's, note cards, or just something to keep with you at all times of the day, and find a Bible verse that keeps you motivated, and keeps your mind in awe of God. I have praying attention deficit disorder, so I write my prayers. That I know has helped me grow. Also, memorize Bible verses (or even Christian songs). Keep your mind focused, and your perspective will change.
How's your social life? Have people around you that you can talk to- they can make a world of difference.
It's a daily battle. Usually, with depression, it's against your thoughts. Watch where your thoughts go. Fight back. Change your thinking and don't let yourself be the same person as you were yesterday. In order to get yourself out of where you have ended up, you must have to be willing to change. Want it. Demand it. Fight with everything you have to get it. Just don't give up on life.
I'm kinda going through the same thing you are. I know I am in a depression, and I just hope that what I've learned about it can help you out.

Like I said earlier, feel free to pm me, if we are going through the same thing, we can go through it together.
In Him,
Marie