I am into my 60's, and still physically fine despite a lifetime of severe anxiety/depression/confusion/stress-------(am also working etc...)-----I recommend some positive stress-------exercise costs nothing, (walk, bike, stretch/do floor exercises), and go places that are free/cheap (exhibits, street fairs, talks, anything at all even if you don't think you will be interested)----listen to music (that feels good to you), dance around, and it is OK to yell and cry. Push yourself a bit (no, no fun at first, or second or...)--not easy but worth it. Draw, paint, play like a kid,
(I have been known to walk the streets at night stopping in playgrounds to get on a swing, a slide, flip over a bar...)---you might be able to find a "meetup" group near you that gets together to walk/talk/other----
I think the mindfulness can work, but it takes a long time sometimes, it is easy to give up...mix it up with something else...
And, do things that soothe you (could be a bath/lotion/blowing bubbles/walking dogs for the humane society...?)
You can do things------that is the part that is difficult, because it feels so hopeless, and yet, well, it isn't----and at times knowing that just sucks. (((((((((hug)))))))))