Hi MB, I've just read through this thread first time. Sorry to hear you are struggling with negative thought patterns but good to see that you are making efforts to change it, including posting here.
The post I most relate to on this thread is what RobbyRobot said earlier about "disordered thinking". I really see a lot of myself in that despite of never having had any serious physical health challenges yet. I am also prone to that: getting stuck in my head and sometimes my thought processes get so intense and go everywhere, they become very convoluted and can take me to very dark places if I don't do anything to stop them or turn it around with an activity. It's really a constant dance on the edge between insightful/useful and madness for me even now sober at times.
Sounds like you have a lot of anxiety. That's also a great part of my problem when I get stuck in negative thought patterns, including suicidal ideation. I know that world very intimately and won't get into it in detail because it would not be helpful here. For me the best description for those states is a sort of hypomania (although I've never been diagnosed with anything like that) - can be extremely disturbing and uncomfortable, and tempting to actually dive even more into it rather than resolving and changing it.
You are doing the right things to examine and improve your thought patterns and feelings - I think sometimes the best approach is to just accept them - observe - let them be - then let them go. Remember that they are always transient (like others pointed out above). Just thoughts, not true threats if we don't stir them up and infuse them with terror.
Depeche Mode was the very favorite band of some of my teenage years, I was actually a bit obsessed with them as many of my friends at the time. Typical goth teenagers. They have evolved a lot and I still like them in a different way of course - so cool that you saw them in concert recently!
Be well.