Nanamar the best thing I ever did was to start learning karate nearly twenty four years ago. It is physical (of course) but it's also something you are always learning and refining. I'm not suggesting you should take up karate or any other martial art (though there's no reason why you shouldn't). The reason I'm mentioning it is because, for the duration of the class, I don't have room in my head to think of anything else. So, for ninety minutes, my mind has a rest from everything else. This has seen me through the deaths of my parents and of my husband, and the loss of my stressful job and career as a teacher (a bereavement in itself).
So I'm recommending you to look for a hobby that occupies your mind and body, that gets you out of the house, that progresses from simple to complex, is rewarding in some way i.e. that gives you measurable or visible results and that you can follow in the company of others. Karate gives me all that but classes in anything creative would be good e.g. Sewing/dressmaking, pottery, painting, cake decorating, papercraft/card making, DIY etc. Anything you can take classes in and practise at home, really. It's the learning, progressing and refining that's important. It needs to be something you enjoy and look forward to. Your local authority probably provides classes for adults.
Volunteering is another possibility. Charity shops and food banks (to name just two of many organisations) are often looking for volunteers.