1. Go for a walk.
When you are depressed the chemicals in your brain and body don't work properly. Endorphins, which give you that wonderful content, satisfied feeling are not being released. Doing something simple like going for a walk helps get these chemicals working again. Even if going for a walk is the last thing you feel like doing.
2. Practice Mindfulness.
At its most basic, mindfulness is sitting and focusing your attention on your breathing, for even five or ten minutes a day. When your mind turns to your concerns or your depressive symptoms, as it surely will, all you have to do is bring your attention back to your breathing. For five or ten minutes, this is the only thing you have to concern yourself with. You are learning to give your mind a rest. Over time doing this should help you feel calmer. There are many resources, books, CDs etc on mindfulness.
3. Engage your senses.
>Find things you used to enjoy, even if you don't enjoy them right now, and do them. From something as simple and easy as enjoying sitting on the back step eating a juicy orange, to soaking in a bath, or reading a book on the beach, find simple ways to soothe and take care of yourself that engage at least one of your senses and try to do two of them every day. This will help you re-connect with your body even if it is hard to kindle a sense of pleasure in these activities at the moment.