I think you might find a new kind of mental health benefit from lifting heavy if you are willing to try it. The rest of your life may be somewhat out of your control, or otherwise not making the kind of progress you'd like, but the weights have nice simple numbers on them and you write them down in your log and can see plain as day that yes, you are making real progress. Meanwhile, you can see it in the mirror and feel it when you go to pick something up. Also, you have license to eat more, or at least eat more protein-rich food, which is some of the best food anyway, and it only helps you instead of hurts you. Add a couple sessions of sprints (I do mine on an exercise bike) for your cardio each week. Takes only 15-20 minutes or so for sprints. Then if you have something coming up where you need to have that long slow endurance kind of fitness, take a couple weeks before the event to get your slow cardio in so you'll be ready.
Female, 5'3", 49, Starting weight: 163lbs. Current weight: 135 (more or less).
Starting squat: 45lbs. Heaviest squat: 180 x 2. Heaviest Deadlift: 230 x 2