(((((((((((((teary_me)))))))))))))))
It's true, life is what you make it -- unless you're depressed, and the depression steals away your ability to make any sense of anything anymore. Don't blame yourself for being depressed, you didn't ask for this.
The whole "only you will know" thing is true to a point -- this is your life and your feelings and your depression, but at the same time, the depression has probably taken away a lot of your ability to distinguish a lot of things, like your sense of self-worth, your overall perspective on life, your ability to hope or care about the things you used to. Depression tells us so many lies that it makes it more difficult for us to swallow that "only you will know" mumbo-jumbo, so that means it's going to be harder for you to figure all these things out. Not impossible, mind you -- you can do this, don't give up!
Life is also not easy, that's true. I can't tell you how hard it is meant to be, but I am here and I care and I hope that by posting here you can ease some of that burden.
Finally, I understand not being able to put your thoughts or feelings into words, and the sensation of not really knowing what you're feeling. It's a very familiar state for me. All I can tell you is to keep trying to figure it out, you'll get there eventually.