Im sorry if this seems blunt but can you not see that the trauma you suffered in your childhood is far, far more likely to be a cause of your depression than your posture? Do you not think you could be using this theory so you don’t have to deal with how the abuse affected you?
And pretty much every expert there is does not advocate ‘doing next to nothing’ as a valid treatment for depression. Exercise is known to increase the ‘happy’ hormones and significantly improves depression symptoms.
Ken, I believe you really need to talk to your doctor about what’s going on, all of it.
Just a note, Ken, we try not to say that one person’s depression is worse than someone else - how everybody here is feeling has just as much an impact on their lives as anyone else’s does.