i have depression too, its makes everything very hard. its not just a bad mood.
personally, I don't believe in depression, I believe in stress.
Your R-complex is constructed in a certain way, expecting certain things from its environment, and to the extent that your lifestyle does not mimic the life of an African savannah tribesman, you are under primal stress. Many "hobbies" are based on trying to recreate lost elements of primal life - camping, gardening, golfing, rock climbing and on and on. Test this and see if it changes your state. This lesson was demonstrated to me personally, when, 8 weeks from graduating BA, I broke down emotionally...and my autonomic response was religious retreat (rather than psychiatry), and up at Madonna House (Ontario), they put me to work chopping wood and eating/living in community, and I felt better, instantly
The next area of stress is our ability to imagine risk, and forward plan. To the extent that you let your R-complex run wild, and you actually live like an African tribesman, your forward planning will suck, you will be stressed by your relative spot in the economic pecking order and you will have a large and growing credit card balance. Part of this is ego and is cured through mental reframing regarding materialism, and some of the happiness you will find in the paragraph above, will reduce your need for materialism. Part of this is investing in your credentials, going into work early, leaving late, projecting a better attitude, embracing thrift. Try applying some improvement in this area, and monitor your emotional state. Read Antony Robbins. I started this process as a highschool drop-out "occupy-style" socialist radical - which is a very painful starting point.
The third area of stress is this darned inconvenience of the fact that what you see and feel is a virtual projection from your true self, your eternal IUOC. Your IUOC has a completely different agenda than you do. To the extent that you live in ignorance of this and in opposition to the goals of your IOUC, you will feel stress. Study MBTOE and apply its principles. Monitor the feedback.
So, clean up your primal, practical and poetic dimensions of your life, then come and tell me you are depressed.
You allude to negative voices within your environment. Part of cleaning up your act is gently "moving" away from negative entities, and part of it is taking control of negative entities. Apart from relationships of duty (parents, spouse, children), it is likely most efficient to create extra, but friendly, distance between yourself and negative entities, and rather invest in more supportive, emotionally profitable relationships. There are normally white hats (Tom's rats) and black hats (Toms' anti-rats) in every environment....try to join the white hats. Have nothing to do with trying to fix people, until you have fixed yourself.
With relationships of duty, it is likely most efficient to figure out how to have your own personal Arab spring, and gently restructure how things work, and acquire conflict management skills. Some humility is called for here...as you may actually be the bad guy in the drama....you never really know.
This is a big topic. Does any of this seem helpful? Where would you like to go from here? If none of this makes any sense to you whatsoever, I apologize for getting in your space.
These thoughts are based on my personal journey from being a very stressed, unhappy, depressed dude, to ...well, what I am now - the arrogant, grouchy guy who talks too much ; - )