I'm sorry to hear that you're depressed. Meditation is definitely more difficult at times like that. Maybe rather than this technique you should try something simpler. Just sit with your eyes closed and "follow your breath," some people like to try counting at first. In-breath one, out-breath two, three, four, then start over when you get to ten or so.

I don't know what's bothering so I don't know how to help you. Breathe really deep and long while focusing your attention on the very tip of your nostrils where air comes in and out. Sometimes doing yoga first prepares the body, like doing a headstand if you can. You'd be surprised how much of the tension and frustration is in the BODY. I really hope you feel better.