With all due respect to the others in this thread, I beg to disagree.
As someone who has struggled/continues to struggle with depression myself, let me tell you this, and tell you this urgently:
GET HELP ASAP.
I know what it feels like. It feels like a sixty-pound weight upon your back. It makes it hard to concentrate, makes it hard to study, saps your willpower, your determination, your drive. You can try your best, but sooner or later your depression will strike again, and when it does, you'll be crippled. You'll be paralyzed. No matter how much effort you've put into your studies so far (and I have no doubt you're an intelligent, hard-working student), it will hurt your grades, and then you'll feel even worse as you blame yourself for your perceived failure. How do I know? Because I've been there. I failed out of college as a result of it. Granted, I was able to pick myself up, go to a Junior College for a year and then transfer back into another university where I eventually finished my degree, but it's not a path I recommend for anybody.
Please, please, please, take my advice and get some help, if you can. There's no shame in making appointments to see a psychiatrist/psychologist, if you can. Doing so demonstrates that you have acknowledged the problem and are working to solve it. If that's not an option, most schools have a counseling service that you can and should take advantage of. Sometimes just being able to talk to someone about your anxieties, even if it's a complete stranger, can be a huge aid.
Realize that your low GPA isn't because you're a bad student. You can be a highly intelligent and hard-working individual, as I said, and still suffer from motivational problems thanks to depression. It's a handicap that can be overcome, but it's a handicap nevertheless. And the sooner you recognize the handicap for what it is, and work to address it, the better off you'll be.
Depression is real. You need to address that first before you can tackle the issue of your academic performance. Depending on your diagnosis, you might even want to consider medication, but at the very least--at the very least--look into getting some sort of counseling.
If you want to talk about this further, please PM me. Like I said, I've been there, done that, and have the scars.