OK, so what do you want to solve your MH issues? Drugs, counselling?
You may not like to hear it but the "stiff upper lip, just get on with it" attitude does actually help for lots of people, and lots find it better than becoming reliant on drugs or sitting in a counsellor's office dwelling on all the negatives!
My Mother had dementia, just about still able to live on her own. I know instantly when I talk to her whether she's been out for a walk that morning -she's happier, more coherent, etc., even if she's just walked around the block. On days when she's not been out, she's morbidly depressed, can barely hold a conversation, etc.
Moving the body causes better blood flow all around the body and more importantly to the brain, it releases different kinds of "signals".
I walk to/from work every day when I can, i.e. around 95% of the days when it's not torrential rain, and perfectly possible to walk without getting drenched. The vast majority of days, there's no rain at all. On the very few days that I drive instead of walking, I feel it, I'm more sluggish, body and brain, often miserable, etc.
Presumably you go out for walks on all the days when it's not raining?