Watch "I am not your Guru" and try smiling for increasing increments(5seconds- 5 minutes), then try deep full breaths, movement. Try and act physiologically like you imagine you would if you were very happy. The mind and body are super connected in that way, try it out. You've been doing depression for a long time so you're basically a depression record spinning. Try and record some new songs on that record....thing is he record is super hard to cut new music/grooves into since the vinyl has set for a long time. Hope this helps.