lost my spirit

My spirit has been lost recently. I don't know why. I think too much all of day about my tasks, my dreams, but no one can be done(it's better to say: none of them is done because some of them can be done if not all). Is Can anybody can give me some advice to make spirit come back ? thank you .............

I think it's better to have a deep breath and not to worry and start with the most important  and forget about the rest. That how I do when I feel depressed.