It's nice to see an update from you. I have wondered how you are and now the new job is going.
Personally, I wouldn't be too alarmed about the somewhat darkness of your moods. Over the years I've had instances where I thought some of the same things as you, never acted on them they were just fleeting thoughts. Besides the holidays are supposed to be the time of year that more people are affected by depression and sadness (go figure). I'd say just keep your awareness and if they start to become more predominant instead of just an occasional thought or start affecting your everyday life, i.e. withdrawing from people, staying in bed and not getting out, etc. then seek out someone to talk to about them. Of course I'm no therapist, didn't even sleep at a Holiday Express last night, so take my advice with a grain of salt.
You seem very locked in and engaged in regard to your S14's struggles. Teenage years are so tough, especially for us parents! We just want the best for our kids and it's so hard when we see them either hurting or making decisions that we know aren't the best for them. My D16 had some real struggles last year and into early this year. It was difficult watching her go through that and I had a lot of anxiety wondering what was the best way to deal with her so that it would move her in the right direction and not make things worse. Fortunately, she has rebounded and is doing much better, in fact really good these days. I wish I knew what it was that moved her to chart a more positive course in her life - but I'm happy with the end result.
Very cool that you are going to be stepping out and doing the open mic thing. To me this is another indicator to not be too concerned about the mood stuff. You're willing to put yourself out there and take on new challenges. It would be cool to hear you play!