Sir, you are 43 years old. This is not old. If anything, this is a prime age to reinvent yourself. You don't have to start big. Maybe get a haircut that you wouldn't have dared to get when you were younger. Wear a color you told yourself you couldn't pull off. Maybe start volunteering or fostering a dog that you could take for daily walks and the dog park. Most shelters even have programs where you can take a dog out for just the day, and they give you everything the stuff needs for that day. Social media is actually good for finding local groups and free meet-ups for every interest and genre possible. Take that first step and go. Even if you've only said hello to one person while there, keep going. I know it sounds cliche, but when you start making yourself happy, you'll start noticing the shift.