The brilliant thing about your outlook is that you realise there is a problem. Although it could be said that a few of these behaviours are indicitive of depression I would tend to say that you are exhibiting the symptoms of anxiety.
The important thing to remember is that the way you feel is influenced by a multitude of controllable factors,such as activity, diet, mental focus, and fatigue, than uncontrollable (or those with minimal controllable), weather, genetics, and occupation.
The practical ideas expressed previously, exercise, relaxation techniques, and refocusing activities will work well.
My hallucination is that you are feeling very enclosed and even suffering from sleeping difficulties. In this instance, meditation is perhaps the number one activity you can partake.
Concerning work, I would guess that you are more of a desk jockey than physical labourer. So I would investigate relaxation techniques at work such as meditation breaks, postural techniques ala Cressey and Robertson), problem solving skills training, and conflict management.
Another ally of yours is Stephen Covey’s work on the ‘Time Management Matrix’ which will help in time management and alleviate job and life stress.
Long Live The Body Science